gpu/command_buffer/client/gles2_implementation.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// A class to emulate GLES2 over command buffers.

#include "gpu/command_buffer/client/gles2_implementation.h"

#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#include <GLES2/gl2extchromium.h>
#include <GLES3/gl3.h>
#include <stddef.h>
#include <stdint.h>
#include <algorithm>
#include <map>
#include <set>
#include <sstream>
#include <string>
#include "base/atomic_sequence_num.h"
#include "base/bits.h"
#include "base/compiler_specific.h"
#include "base/containers/span.h"
#include "base/numerics/safe_math.h"
#include "base/strings/string_split.h"
#include "base/strings/stringprintf.h"
#include "base/sys_info.h"
#include "base/threading/thread_task_runner_handle.h"
#include "base/trace_event/memory_allocator_dump.h"
#include "base/trace_event/memory_dump_manager.h"
#include "base/trace_event/process_memory_dump.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "gpu/command_buffer/client/buffer_tracker.h"
#include "gpu/command_buffer/client/gles2_cmd_helper.h"
#include "gpu/command_buffer/client/gpu_control.h"
#include "gpu/command_buffer/client/program_info_manager.h"
#include "gpu/command_buffer/client/query_tracker.h"
#include "gpu/command_buffer/client/readback_buffer_shadow_tracker.h"
#include "gpu/command_buffer/client/shared_memory_limits.h"
#include "gpu/command_buffer/client/transfer_buffer.h"
#include "gpu/command_buffer/client/vertex_array_object_manager.h"
#include "gpu/command_buffer/common/context_creation_attribs.h"
#include "gpu/command_buffer/common/id_allocator.h"
#include "gpu/command_buffer/common/swap_buffers_complete_params.h"
#include "gpu/command_buffer/common/sync_token.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/rect_f.h"

#if !defined(__native_client__)
#include "ui/gfx/color_space.h"
#include "ui/gfx/ipc/color/gfx_param_traits.h"
#endif

#if defined(GPU_CLIENT_DEBUG)
#define GPU_CLIENT_SINGLE_THREAD_CHECK() \
  DeferErrorCallbacks deferrer(this);    \
  SingleThreadChecker checker(this);
#else  // !defined(GPU_CLIENT_DEBUG)
#define GPU_CLIENT_SINGLE_THREAD_CHECK() DeferErrorCallbacks deferrer(this);
#endif  // defined(GPU_CLIENT_DEBUG)

// Check that destination pointers point to initialized memory.
// When the context is lost, calling GL function has no effect so if destination
// pointers point to initialized memory it can often lead to crash bugs. eg.
//
// GLsizei len;
// glGetShaderSource(shader, max_size, &len, buffer);
// std::string src(buffer, buffer + len);  // len can be uninitialized here!!!
//
// Because this check is not official GL this check happens only on Chrome code,
// not Pepper.
//
// If it was up to us we'd just always write to the destination but the OpenGL
// spec defines the behavior of OpenGL functions, not us. :-(
#if defined(__native_client__) || defined(GLES2_CONFORMANCE_TESTS)
#define GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v)
#define GPU_CLIENT_DCHECK(v)
#elif defined(GPU_DCHECK)
#define GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v) GPU_DCHECK(v)
#define GPU_CLIENT_DCHECK(v) GPU_DCHECK(v)
#elif defined(DCHECK)
#define GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v) DCHECK(v)
#define GPU_CLIENT_DCHECK(v) DCHECK(v)
#else
#define GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v) ASSERT(v)
#define GPU_CLIENT_DCHECK(v) ASSERT(v)
#endif

#define GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION(type, ptr) \
  GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(          \
      ptr &&                                                     \
      (ptr[0] == static_cast<type>(0) || ptr[0] == static_cast<type>(-1)));

#define GPU_CLIENT_VALIDATE_DESTINATION_OPTIONAL_INITALIZATION(type, ptr) \
  GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(                   \
      !ptr ||                                                             \
      (ptr[0] == static_cast<type>(0) || ptr[0] == static_cast<type>(-1)));

namespace gpu {
namespace gles2 {

namespace {

void CopyRectToBuffer(const void* pixels,
                      uint32_t height,
                      uint32_t unpadded_row_size,
                      uint32_t pixels_padded_row_size,
                      void* buffer,
                      uint32_t buffer_padded_row_size) {
  if (height == 0)
    return;
  const int8_t* source = static_cast<const int8_t*>(pixels);
  int8_t* dest = static_cast<int8_t*>(buffer);
  if (pixels_padded_row_size != buffer_padded_row_size) {
    for (uint32_t ii = 0; ii < height; ++ii) {
      memcpy(dest, source, unpadded_row_size);
      dest += buffer_padded_row_size;
      source += pixels_padded_row_size;
    }
  } else {
    uint32_t size = (height - 1) * pixels_padded_row_size + unpadded_row_size;
    memcpy(dest, source, size);
  }
}

// A 32-bit and 64-bit compatible way of converting a pointer to a GLuint.
GLuint ToGLuint(const void* ptr) {
  return static_cast<GLuint>(reinterpret_cast<size_t>(ptr));
}

static base::AtomicSequenceNumber g_flush_id;

uint32_t GenerateNextFlushId() {
  return static_cast<uint32_t>(g_flush_id.GetNext());
}

bool IsReadbackUsage(GLenum usage) {
  return usage == GL_STREAM_READ || usage == GL_DYNAMIC_READ ||
         usage == GL_STATIC_READ;
}

}  // anonymous namespace

GLES2Implementation::GLStaticState::GLStaticState() = default;

GLES2Implementation::GLStaticState::~GLStaticState() = default;

GLES2Implementation::DeferErrorCallbacks::DeferErrorCallbacks(
    GLES2Implementation* gles2_implementation)
    : gles2_implementation_(gles2_implementation) {
  DCHECK_EQ(false, gles2_implementation_->deferring_error_callbacks_);
  gles2_implementation_->deferring_error_callbacks_ = true;
}

GLES2Implementation::DeferErrorCallbacks::~DeferErrorCallbacks() {
  DCHECK_EQ(true, gles2_implementation_->deferring_error_callbacks_);
  gles2_implementation_->deferring_error_callbacks_ = false;
  gles2_implementation_->CallDeferredErrorCallbacks();
}

GLES2Implementation::DeferredErrorCallback::DeferredErrorCallback(
    std::string message,
    int32_t id)
    : message(std::move(message)), id(id) {}

GLES2Implementation::SingleThreadChecker::SingleThreadChecker(
    GLES2Implementation* gles2_implementation)
    : gles2_implementation_(gles2_implementation) {
  CHECK_EQ(0, gles2_implementation_->use_count_);
  ++gles2_implementation_->use_count_;
}

GLES2Implementation::SingleThreadChecker::~SingleThreadChecker() {
  --gles2_implementation_->use_count_;
  CHECK_EQ(0, gles2_implementation_->use_count_);
}

GLES2Implementation::GLES2Implementation(
    GLES2CmdHelper* helper,
    scoped_refptr<ShareGroup> share_group,
    TransferBufferInterface* transfer_buffer,
    bool bind_generates_resource,
    bool lose_context_when_out_of_memory,
    bool support_client_side_arrays,
    GpuControl* gpu_control)
    : ImplementationBase(helper, transfer_buffer, gpu_control),
      helper_(helper),
      chromium_framebuffer_multisample_(kUnknownExtensionStatus),
      pack_alignment_(4),
      pack_row_length_(0),
      pack_skip_pixels_(0),
      pack_skip_rows_(0),
      unpack_alignment_(4),
      unpack_row_length_(0),
      unpack_image_height_(0),
      unpack_skip_rows_(0),
      unpack_skip_pixels_(0),
      unpack_skip_images_(0),
      active_texture_unit_(0),
      bound_framebuffer_(0),
      bound_read_framebuffer_(0),
      bound_renderbuffer_(0),
      current_program_(0),
      bound_array_buffer_(0),
      bound_copy_read_buffer_(0),
      bound_copy_write_buffer_(0),
      bound_pixel_pack_buffer_(0),
      bound_pixel_unpack_buffer_(0),
      bound_transform_feedback_buffer_(0),
      bound_uniform_buffer_(0),
      bound_pixel_pack_transfer_buffer_id_(0),
      bound_pixel_unpack_transfer_buffer_id_(0),
      error_bits_(0),
      lose_context_when_out_of_memory_(lose_context_when_out_of_memory),
      support_client_side_arrays_(support_client_side_arrays),
      use_count_(0),
      flush_id_(0),
      max_extra_transfer_buffer_size_(0),
      current_trace_stack_(0),
      aggressively_free_resources_(false),
      cached_extension_string_(nullptr),
      weak_ptr_factory_(this) {
  DCHECK(helper);

  std::stringstream ss;
  ss << std::hex << this;
  this_in_hex_ = ss.str();

  share_group_ =
      (share_group ? std::move(share_group)
                   : new ShareGroup(
                         bind_generates_resource,
                         gpu_control_->GetCommandBufferID().GetUnsafeValue()));
  DCHECK(share_group_->bind_generates_resource() == bind_generates_resource);

  memset(&reserved_ids_, 0, sizeof(reserved_ids_));
}

gpu::ContextResult GLES2Implementation::Initialize(
    const SharedMemoryLimits& limits) {
  TRACE_EVENT0("gpu", "GLES2Implementation::Initialize");
  auto result = ImplementationBase::Initialize(limits);
  if (result != gpu::ContextResult::kSuccess) {
    return result;
  }

  max_extra_transfer_buffer_size_ = limits.max_mapped_memory_for_texture_upload;

  GLStaticState::ShaderPrecisionMap* shader_precisions =
      &static_state_.shader_precisions;
  capabilities_.VisitPrecisions([shader_precisions](
      GLenum shader, GLenum type, Capabilities::ShaderPrecision* result) {
    const GLStaticState::ShaderPrecisionKey key(shader, type);
    cmds::GetShaderPrecisionFormat::Result cached_result = {
        true, result->min_range, result->max_range, result->precision};
    shader_precisions->insert(std::make_pair(key, cached_result));
  });

  util_.set_num_compressed_texture_formats(
      capabilities_.num_compressed_texture_formats);
  util_.set_num_shader_binary_formats(capabilities_.num_shader_binary_formats);

  texture_units_ = std::make_unique<TextureUnit[]>(
      capabilities_.max_combined_texture_image_units);

  buffer_tracker_ = std::make_unique<BufferTracker>(mapped_memory_.get());
  readback_buffer_shadow_tracker_ =
      std::make_unique<ReadbackBufferShadowTracker>(mapped_memory_.get(),
                                                    helper_);

  for (int i = 0; i < static_cast<int>(IdNamespaces::kNumIdNamespaces); ++i)
    id_allocators_[i].reset(new IdAllocator());

  if (support_client_side_arrays_) {
    GetIdHandler(SharedIdNamespaces::kBuffers)
        ->MakeIds(this, kClientSideArrayId, arraysize(reserved_ids_),
                  &reserved_ids_[0]);
  }

  vertex_array_object_manager_.reset(new VertexArrayObjectManager(
      capabilities_.max_vertex_attribs, reserved_ids_[0], reserved_ids_[1],
      support_client_side_arrays_));

  // GL_BIND_GENERATES_RESOURCE_CHROMIUM state must be the same
  // on Client & Service.
  if (capabilities_.bind_generates_resource_chromium !=
      (share_group_->bind_generates_resource() ? 1 : 0)) {
    SetGLError(GL_INVALID_OPERATION,
               "Initialize",
               "Service bind_generates_resource mismatch.");
    LOG(ERROR) << "ContextResult::kFatalFailure: "
               << "bind_generates_resource mismatch";
    return gpu::ContextResult::kFatalFailure;
  }

  return gpu::ContextResult::kSuccess;
}

GLES2Implementation::~GLES2Implementation() {
  // Make sure the queries are finished otherwise we'll delete the
  // shared memory (mapped_memory_) which will free the memory used
  // by the queries. The GPU process when validating that memory is still
  // shared will fail and abort (ie, it will stop running).
  WaitForCmd();

  query_tracker_.reset();

  // GLES2Implementation::Initialize() could fail before allocating
  // reserved_ids_, so we need delete them carefully.
  if (support_client_side_arrays_ && reserved_ids_[0]) {
    DeleteBuffers(arraysize(reserved_ids_), &reserved_ids_[0]);
  }

  // Release remaining BufferRange mem; This is when a MapBufferRange() is
  // called but not the UnmapBuffer() pair.
  ClearMappedBufferRangeMap();

  // Release any per-context data in share group.
  share_group_->FreeContext(this);

  buffer_tracker_.reset();
  readback_buffer_shadow_tracker_.reset();

  // Make sure the commands make it the service.
  WaitForCmd();
}

GLES2CmdHelper* GLES2Implementation::helper() const {
  return helper_;
}

IdHandlerInterface* GLES2Implementation::GetIdHandler(
    SharedIdNamespaces namespace_id) const {
  return share_group_->GetIdHandler(namespace_id);
}

RangeIdHandlerInterface* GLES2Implementation::GetRangeIdHandler(
    int namespace_id) const {
  return share_group_->GetRangeIdHandler(namespace_id);
}

IdAllocator* GLES2Implementation::GetIdAllocator(
    IdNamespaces namespace_id) const {
  return id_allocators_[static_cast<int>(namespace_id)].get();
}

void GLES2Implementation::OnGpuControlLostContext() {
  // This should never occur more than once.
  DCHECK(!lost_context_callback_run_);
  lost_context_callback_run_ = true;
  share_group_->Lose();
  if (!lost_context_callback_.is_null()) {
    std::move(lost_context_callback_).Run();
  }
}

void GLES2Implementation::OnGpuControlLostContextMaybeReentrant() {
  // Queries for lost context state should immediately reflect reality,
  // but don't call out to clients yet to avoid them re-entering this
  // class.
  share_group_->Lose();
}

void GLES2Implementation::OnGpuControlErrorMessage(const char* message,
                                                   int32_t id) {
  SendErrorMessage(message, id);
}

void GLES2Implementation::OnGpuControlSwapBuffersCompleted(
    const SwapBuffersCompleteParams& params) {
  auto found = pending_swap_callbacks_.find(params.swap_response.swap_id);
  if (found == pending_swap_callbacks_.end())
    return;

  std::move(found->second).Run(params);
  pending_swap_callbacks_.erase(found);
}

void GLES2Implementation::SendErrorMessage(std::string message, int32_t id) {
  if (error_message_callback_.is_null())
    return;

  if (deferring_error_callbacks_) {
    deferred_error_callbacks_.emplace_back(std::move(message), id);
    return;
  }

  error_message_callback_.Run(message.c_str(), id);
}

void GLES2Implementation::CallDeferredErrorCallbacks() {
  if (error_message_callback_.is_null()) {
    // User probably cleared this out.
    deferred_error_callbacks_.clear();
    return;
  }

  std::deque<DeferredErrorCallback> local_callbacks;
  std::swap(deferred_error_callbacks_, local_callbacks);
  for (auto c : local_callbacks) {
    error_message_callback_.Run(c.message.c_str(), c.id);
  }
}

void GLES2Implementation::OnSwapBufferPresented(
    uint64_t swap_id,
    const gfx::PresentationFeedback& feedback) {
  auto found = pending_presentation_callbacks_.find(swap_id);
  if (found == pending_presentation_callbacks_.end())
    return;
  std::move(found->second).Run(feedback);
  pending_presentation_callbacks_.erase(found);
}

void GLES2Implementation::FreeSharedMemory(void* mem) {
  mapped_memory_->FreePendingToken(mem, helper_->InsertToken());
}

GLuint GLES2Implementation::CreateGpuFenceCHROMIUM() {
  GLuint client_id = GetIdAllocator(IdNamespaces::kGpuFences)
                         ->AllocateIDAtOrAbove(last_gpu_fence_id_ + 1);
  // Out of paranoia, don't allow IDs to wrap around to avoid potential
  // collisions on reuse. The space of 2^32 IDs is enough for over a year of
  // allocating two per frame at 60fps. TODO(crbug.com/790550): Revisit if this
  // is an issue, for example by deferring ID release if they would be reissued
  // too soon.
  CHECK(client_id > last_gpu_fence_id_) << "ID wrap prevented";
  last_gpu_fence_id_ = client_id;
  helper_->CreateGpuFenceINTERNAL(client_id);
  GPU_CLIENT_LOG("returned " << client_id);
  CheckGLError();
  return client_id;
}

GLuint GLES2Implementation::CreateClientGpuFenceCHROMIUM(
    ClientGpuFence source) {
  GLuint client_id = GetIdAllocator(IdNamespaces::kGpuFences)
                         ->AllocateIDAtOrAbove(last_gpu_fence_id_ + 1);
  // See CreateGpuFenceCHROMIUM comment re wraparound.
  CHECK(client_id > last_gpu_fence_id_) << "ID wrap prevented";
  last_gpu_fence_id_ = client_id;

  // Create the service-side GpuFenceEntry via gpu_control. This is guaranteed
  // to arrive before any future GL helper_ commands on this stream, so it's
  // safe to use the client_id generated here in following commands such as
  // WaitGpuFenceCHROMIUM without explicit flushing.
  gpu_control_->CreateGpuFence(client_id, source);

  GPU_CLIENT_LOG("returned " << client_id);
  CheckGLError();
  return client_id;
}

void GLES2Implementation::DestroyGpuFenceCHROMIUMHelper(GLuint client_id) {
  if (GetIdAllocator(IdNamespaces::kGpuFences)->InUse(client_id)) {
    GetIdAllocator(IdNamespaces::kGpuFences)->FreeID(client_id);
    helper_->DestroyGpuFenceCHROMIUM(client_id);
  } else {
    SetGLError(GL_INVALID_VALUE, "glDestroyGpuFenceCHROMIUM",
               "id not created by this context.");
  }
}

void GLES2Implementation::SetAggressivelyFreeResources(
    bool aggressively_free_resources) {
  TRACE_EVENT1("gpu", "GLES2Implementation::SetAggressivelyFreeResources",
               "aggressively_free_resources", aggressively_free_resources);
  aggressively_free_resources_ = aggressively_free_resources;

  if (aggressively_free_resources_ && helper_->HaveRingBuffer()) {
    // Ensure that we clean up as much cache memory as possible and fully flush.
    FlushDriverCachesCHROMIUM();

    // Flush will delete transfer buffer resources if
    // |aggressively_free_resources_| is true.
    Flush();
  } else {
    ShallowFlushCHROMIUM();
  }
}

bool GLES2Implementation::IsExtensionAvailable(const char* ext) {
  const char* extensions =
      reinterpret_cast<const char*>(GetStringHelper(GL_EXTENSIONS));
  if (!extensions)
    return false;

  int length = strlen(ext);
  while (true) {
    int n = strcspn(extensions, " ");
    if (n == length && 0 == strncmp(ext, extensions, length)) {
      return true;
    }
    if ('\0' == extensions[n]) {
      return false;
    }
    extensions += n + 1;
  }
}

bool GLES2Implementation::IsExtensionAvailableHelper(
    const char* extension, ExtensionStatus* status) {
  switch (*status) {
    case kAvailableExtensionStatus:
      return true;
    case kUnavailableExtensionStatus:
      return false;
    default: {
      bool available = IsExtensionAvailable(extension);
      *status = available ? kAvailableExtensionStatus :
                            kUnavailableExtensionStatus;
      return available;
    }
  }
}

bool GLES2Implementation::IsChromiumFramebufferMultisampleAvailable() {
  return IsExtensionAvailableHelper(
      "GL_CHROMIUM_framebuffer_multisample",
      &chromium_framebuffer_multisample_);
}

const std::string& GLES2Implementation::GetLogPrefix() const {
  const std::string& prefix(debug_marker_manager_.GetMarker());
  return prefix.empty() ? this_in_hex_ : prefix;
}

GLenum GLES2Implementation::GetError() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetError()");
  GLenum err = GetGLError();
  GPU_CLIENT_LOG("returned " << GLES2Util::GetStringError(err));
  return err;
}

GLenum GLES2Implementation::GetGLError() {
  TRACE_EVENT0("gpu", "GLES2::GetGLError");
  // Check the GL error first, then our wrapped error.
  typedef cmds::GetError::Result Result;
  Result* result = GetResultAs<Result*>();
  // If we couldn't allocate a result the context is lost.
  if (!result) {
    return GL_NO_ERROR;
  }
  *result = GL_NO_ERROR;
  helper_->GetError(GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  GLenum error = *result;
  if (error == GL_NO_ERROR) {
    error = GetClientSideGLError();
  } else {
    // There was an error, clear the corresponding wrapped error.
    error_bits_ &= ~GLES2Util::GLErrorToErrorBit(error);
  }
  return error;
}

#if defined(GL_CLIENT_FAIL_GL_ERRORS)
void GLES2Implementation::FailGLError(GLenum error) {
  if (error != GL_NO_ERROR) {
    NOTREACHED() << "Error";
  }
}
// NOTE: Calling GetGLError overwrites data in the result buffer.
void GLES2Implementation::CheckGLError() {
  FailGLError(GetGLError());
}
#endif  // defined(GPU_CLIENT_FAIL_GL_ERRORS)

void GLES2Implementation::SetGLError(
    GLenum error, const char* function_name, const char* msg) {
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] Client Synthesized Error: "
                 << GLES2Util::GetStringError(error) << ": "
                 << function_name << ": " << msg);
  FailGLError(error);
  if (msg) {
    last_error_ = msg;
  }
  if (!error_message_callback_.is_null()) {
    std::string temp(GLES2Util::GetStringError(error)  + " : " +
                     function_name + ": " + (msg ? msg : ""));
    SendErrorMessage(temp.c_str(), 0);
  }
  error_bits_ |= GLES2Util::GLErrorToErrorBit(error);

  if (error == GL_OUT_OF_MEMORY && lose_context_when_out_of_memory_) {
    helper_->LoseContextCHROMIUM(GL_GUILTY_CONTEXT_RESET_ARB,
                                 GL_UNKNOWN_CONTEXT_RESET_ARB);
  }
}

void GLES2Implementation::SetGLErrorInvalidEnum(
    const char* function_name, GLenum value, const char* label) {
  SetGLError(GL_INVALID_ENUM, function_name,
             (std::string(label) + " was " +
              GLES2Util::GetStringEnum(value)).c_str());
}

void GLES2Implementation::Disable(GLenum cap) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDisable("
                 << GLES2Util::GetStringCapability(cap) << ")");
  bool changed = false;
  if (!state_.SetCapabilityState(cap, false, &changed) || changed) {
    helper_->Disable(cap);
  }
  CheckGLError();
}

void GLES2Implementation::Enable(GLenum cap) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glEnable("
                 << GLES2Util::GetStringCapability(cap) << ")");
  bool changed = false;
  if (!state_.SetCapabilityState(cap, true, &changed) || changed) {
    helper_->Enable(cap);
  }
  CheckGLError();
}

GLboolean GLES2Implementation::IsEnabled(GLenum cap) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glIsEnabled("
                 << GLES2Util::GetStringCapability(cap) << ")");
  bool state = false;
  if (!state_.GetEnabled(cap, &state)) {
    typedef cmds::IsEnabled::Result Result;
    Result* result = GetResultAs<Result*>();
    if (!result) {
      return GL_FALSE;
    }
    *result = 0;
    helper_->IsEnabled(cap, GetResultShmId(), GetResultShmOffset());
    WaitForCmd();
    state = (*result) != 0;
  }

  GPU_CLIENT_LOG("returned " << state);
  CheckGLError();
  return state;
}

bool GLES2Implementation::GetHelper(GLenum pname, GLint* params) {
  // TODO(zmo): For all the BINDING points, there is a possibility where
  // resources are shared among multiple contexts, that the cached points
  // are invalid. It is not a problem for now, but once we allow resource
  // sharing in WebGL, we need to implement a mechanism to allow correct
  // client side binding points tracking.  crbug.com/465562.

  // ES2 parameters.
  switch (pname) {
    case GL_ACTIVE_TEXTURE:
      *params = active_texture_unit_ + GL_TEXTURE0;
      return true;
    case GL_ARRAY_BUFFER_BINDING:
      *params = bound_array_buffer_;
      return true;
    case GL_ELEMENT_ARRAY_BUFFER_BINDING:
      *params =
          vertex_array_object_manager_->bound_element_array_buffer();
      return true;
    case GL_FRAMEBUFFER_BINDING:
      *params = bound_framebuffer_;
      return true;
    case GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS:
      *params = capabilities_.max_combined_texture_image_units;
      return true;
    case GL_MAX_CUBE_MAP_TEXTURE_SIZE:
      *params = capabilities_.max_cube_map_texture_size;
      return true;
    case GL_MAX_FRAGMENT_UNIFORM_VECTORS:
      *params = capabilities_.max_fragment_uniform_vectors;
      return true;
    case GL_MAX_RENDERBUFFER_SIZE:
      *params = capabilities_.max_renderbuffer_size;
      return true;
    case GL_MAX_TEXTURE_IMAGE_UNITS:
      *params = capabilities_.max_texture_image_units;
      return true;
    case GL_MAX_TEXTURE_SIZE:
      *params = capabilities_.max_texture_size;
      return true;
    case GL_MAX_VARYING_VECTORS:
      *params = capabilities_.max_varying_vectors;
      return true;
    case GL_MAX_VERTEX_ATTRIBS:
      *params = capabilities_.max_vertex_attribs;
      return true;
    case GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:
      *params = capabilities_.max_vertex_texture_image_units;
      return true;
    case GL_MAX_VERTEX_UNIFORM_VECTORS:
      *params = capabilities_.max_vertex_uniform_vectors;
      return true;
    case GL_MAX_VIEWPORT_DIMS:
      if (capabilities_.max_viewport_width > 0 &&
          capabilities_.max_viewport_height > 0) {
        params[0] = capabilities_.max_viewport_width;
        params[1] = capabilities_.max_viewport_height;
        return true;
      }
      // If they are not cached on the client side yet, query the service side.
      return false;
    case GL_NUM_COMPRESSED_TEXTURE_FORMATS:
      *params = capabilities_.num_compressed_texture_formats;
      return true;
    case GL_NUM_SHADER_BINARY_FORMATS:
      *params = capabilities_.num_shader_binary_formats;
      return true;
    case GL_RENDERBUFFER_BINDING:
      *params = bound_renderbuffer_;
      return true;
    case GL_TEXTURE_BINDING_2D:
      *params = texture_units_[active_texture_unit_].bound_texture_2d;
      return true;
    case GL_TEXTURE_BINDING_CUBE_MAP:
      *params = texture_units_[active_texture_unit_].bound_texture_cube_map;
      return true;

    // Non-standard parameters.
    case GL_TEXTURE_BINDING_EXTERNAL_OES:
      *params =
          texture_units_[active_texture_unit_].bound_texture_external_oes;
      return true;
    case GL_PIXEL_PACK_TRANSFER_BUFFER_BINDING_CHROMIUM:
      *params = bound_pixel_pack_transfer_buffer_id_;
      return true;
    case GL_PIXEL_UNPACK_TRANSFER_BUFFER_BINDING_CHROMIUM:
      *params = bound_pixel_unpack_transfer_buffer_id_;
      return true;
    case GL_READ_FRAMEBUFFER_BINDING:
      if (capabilities_.major_version >= 3 ||
          IsChromiumFramebufferMultisampleAvailable()) {
        *params = bound_read_framebuffer_;
        return true;
      }
      break;
    case GL_TIMESTAMP_EXT:
      // We convert all GPU timestamps to CPU time.
      *params = base::saturated_cast<GLint>(
          (base::TimeTicks::Now() - base::TimeTicks()).InMicroseconds()
          * base::Time::kNanosecondsPerMicrosecond);
      return true;
    case GL_GPU_DISJOINT_EXT:
      *params = static_cast<GLint>(query_tracker_->CheckAndResetDisjoint());
      return true;

    case GL_VIEWPORT:
      if (state_.viewport_width > 0 &&
          state_.viewport_height > 0 &&
          capabilities_.max_viewport_width > 0 &&
          capabilities_.max_viewport_height > 0) {
        params[0] = state_.viewport_x;
        params[1] = state_.viewport_y;
        params[2] = std::min(state_.viewport_width,
                             capabilities_.max_viewport_width);
        params[3] = std::min(state_.viewport_height,
                             capabilities_.max_viewport_height);
        return true;
      }
      // If they haven't been cached on the client side, go to service side
      // to query the underlying driver.
      return false;

    // Non-cached parameters.
    case GL_ALIASED_LINE_WIDTH_RANGE:
    case GL_ALIASED_POINT_SIZE_RANGE:
    case GL_ALPHA_BITS:
    case GL_BLEND:
    case GL_BLEND_COLOR:
    case GL_BLEND_DST_ALPHA:
    case GL_BLEND_DST_RGB:
    case GL_BLEND_EQUATION_ALPHA:
    case GL_BLEND_EQUATION_RGB:
    case GL_BLEND_SRC_ALPHA:
    case GL_BLEND_SRC_RGB:
    case GL_BLUE_BITS:
    case GL_COLOR_CLEAR_VALUE:
    case GL_COLOR_WRITEMASK:
    case GL_COMPRESSED_TEXTURE_FORMATS:
    case GL_CULL_FACE:
    case GL_CULL_FACE_MODE:
    case GL_CURRENT_PROGRAM:
    case GL_DEPTH_BITS:
    case GL_DEPTH_CLEAR_VALUE:
    case GL_DEPTH_FUNC:
    case GL_DEPTH_RANGE:
    case GL_DEPTH_TEST:
    case GL_DEPTH_WRITEMASK:
    case GL_DITHER:
    case GL_FRONT_FACE:
    case GL_GENERATE_MIPMAP_HINT:
    case GL_GREEN_BITS:
    case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
    case GL_IMPLEMENTATION_COLOR_READ_TYPE:
    case GL_LINE_WIDTH:
    case GL_PACK_ALIGNMENT:
    case GL_POLYGON_OFFSET_FACTOR:
    case GL_POLYGON_OFFSET_FILL:
    case GL_POLYGON_OFFSET_UNITS:
    case GL_RED_BITS:
    case GL_SAMPLE_ALPHA_TO_COVERAGE:
    case GL_SAMPLE_BUFFERS:
    case GL_SAMPLE_COVERAGE:
    case GL_SAMPLE_COVERAGE_INVERT:
    case GL_SAMPLE_COVERAGE_VALUE:
    case GL_SAMPLES:
    case GL_SCISSOR_BOX:
    case GL_SCISSOR_TEST:
    case GL_SHADER_BINARY_FORMATS:
    case GL_SHADER_COMPILER:
    case GL_STENCIL_BACK_FAIL:
    case GL_STENCIL_BACK_FUNC:
    case GL_STENCIL_BACK_PASS_DEPTH_FAIL:
    case GL_STENCIL_BACK_PASS_DEPTH_PASS:
    case GL_STENCIL_BACK_REF:
    case GL_STENCIL_BACK_VALUE_MASK:
    case GL_STENCIL_BACK_WRITEMASK:
    case GL_STENCIL_BITS:
    case GL_STENCIL_CLEAR_VALUE:
    case GL_STENCIL_FAIL:
    case GL_STENCIL_FUNC:
    case GL_STENCIL_PASS_DEPTH_FAIL:
    case GL_STENCIL_PASS_DEPTH_PASS:
    case GL_STENCIL_REF:
    case GL_STENCIL_TEST:
    case GL_STENCIL_VALUE_MASK:
    case GL_STENCIL_WRITEMASK:
    case GL_SUBPIXEL_BITS:
    case GL_UNPACK_ALIGNMENT:
      return false;
    default:
      break;
  }

  if (capabilities_.major_version < 3) {
    return false;
  }

  // ES3 parameters.
  switch (pname) {
    case GL_COPY_READ_BUFFER_BINDING:
      *params = bound_copy_read_buffer_;
      return true;
    case GL_COPY_WRITE_BUFFER_BINDING:
      *params = bound_copy_write_buffer_;
      return true;
    case GL_MAJOR_VERSION:
      *params = capabilities_.major_version;
      return true;
    case GL_MAX_3D_TEXTURE_SIZE:
      *params = capabilities_.max_3d_texture_size;
      return true;
    case GL_MAX_ARRAY_TEXTURE_LAYERS:
      *params = capabilities_.max_array_texture_layers;
      return true;
    case GL_MAX_COLOR_ATTACHMENTS:
      *params = capabilities_.max_color_attachments;
      return true;
    case GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS:
      *params = static_cast<GLint>(
          capabilities_.max_combined_fragment_uniform_components);
      return true;
    case GL_MAX_COMBINED_UNIFORM_BLOCKS:
      *params = capabilities_.max_combined_uniform_blocks;
      return true;
    case GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS:
      *params = static_cast<GLint>(
          capabilities_.max_combined_vertex_uniform_components);
      return true;
    case GL_MAX_DRAW_BUFFERS:
      *params = capabilities_.max_draw_buffers;
      return true;
    case GL_MAX_ELEMENT_INDEX:
      *params = static_cast<GLint>(capabilities_.max_element_index);
      return true;
    case GL_MAX_ELEMENTS_INDICES:
      *params = capabilities_.max_elements_indices;
      return true;
    case GL_MAX_ELEMENTS_VERTICES:
      *params = capabilities_.max_elements_vertices;
      return true;
    case GL_MAX_FRAGMENT_INPUT_COMPONENTS:
      *params = capabilities_.max_fragment_input_components;
      return true;
    case GL_MAX_FRAGMENT_UNIFORM_BLOCKS:
      *params = capabilities_.max_fragment_uniform_blocks;
      return true;
    case GL_MAX_FRAGMENT_UNIFORM_COMPONENTS:
      *params = capabilities_.max_fragment_uniform_components;
      return true;
    case GL_MAX_PROGRAM_TEXEL_OFFSET:
      *params = capabilities_.max_program_texel_offset;
      return true;
    case GL_MAX_SAMPLES:
      *params = capabilities_.max_samples;
      return true;
    case GL_MAX_SERVER_WAIT_TIMEOUT:
      *params = static_cast<GLint>(capabilities_.max_server_wait_timeout);
      return true;
    case GL_MAX_TEXTURE_LOD_BIAS:
      *params = static_cast<GLint>(capabilities_.max_texture_lod_bias);
      return true;
    case GL_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS:
      *params = capabilities_.max_transform_feedback_interleaved_components;
      return true;
    case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS:
      *params = capabilities_.max_transform_feedback_separate_attribs;
      return true;
    case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS:
      *params = capabilities_.max_transform_feedback_separate_components;
      return true;
    case GL_MAX_UNIFORM_BLOCK_SIZE:
      *params = static_cast<GLint>(capabilities_.max_uniform_block_size);
      return true;
    case GL_MAX_UNIFORM_BUFFER_BINDINGS:
      *params = capabilities_.max_uniform_buffer_bindings;
      return true;
    case GL_MAX_VARYING_COMPONENTS:
      *params = capabilities_.max_varying_components;
      return true;
    case GL_MAX_VERTEX_OUTPUT_COMPONENTS:
      *params = capabilities_.max_vertex_output_components;
      return true;
    case GL_MAX_VERTEX_UNIFORM_BLOCKS:
      *params = capabilities_.max_vertex_uniform_blocks;
      return true;
    case GL_MAX_VERTEX_UNIFORM_COMPONENTS:
      *params = capabilities_.max_vertex_uniform_components;
      return true;
    case GL_MIN_PROGRAM_TEXEL_OFFSET:
      *params = capabilities_.min_program_texel_offset;
      return true;
    case GL_MINOR_VERSION:
      *params = capabilities_.minor_version;
      return true;
    case GL_NUM_EXTENSIONS:
      UpdateCachedExtensionsIfNeeded();
      *params = cached_extensions_.size();
      return true;
    case GL_NUM_PROGRAM_BINARY_FORMATS:
      *params = capabilities_.num_program_binary_formats;
      return true;
    case GL_PACK_SKIP_PIXELS:
      *params = pack_skip_pixels_;
      return true;
    case GL_PACK_SKIP_ROWS:
      *params = pack_skip_rows_;
      return true;
    case GL_PIXEL_PACK_BUFFER_BINDING:
      *params = bound_pixel_pack_buffer_;
      return true;
    case GL_PIXEL_UNPACK_BUFFER_BINDING:
      *params = bound_pixel_unpack_buffer_;
      return true;
    case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
      *params = bound_transform_feedback_buffer_;
      return true;
    case GL_UNIFORM_BUFFER_BINDING:
      *params = bound_uniform_buffer_;
      return true;
    case GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT:
      *params = capabilities_.uniform_buffer_offset_alignment;
      return true;
    case GL_UNPACK_SKIP_IMAGES:
      *params = unpack_skip_images_;
      return true;
    case GL_UNPACK_SKIP_PIXELS:
      *params = unpack_skip_pixels_;
      return true;
    case GL_UNPACK_SKIP_ROWS:
      *params = unpack_skip_rows_;
      return true;

    // Non-cached ES3 parameters.
    case GL_DRAW_BUFFER0:
    case GL_DRAW_BUFFER1:
    case GL_DRAW_BUFFER2:
    case GL_DRAW_BUFFER3:
    case GL_DRAW_BUFFER4:
    case GL_DRAW_BUFFER5:
    case GL_DRAW_BUFFER6:
    case GL_DRAW_BUFFER7:
    case GL_DRAW_BUFFER8:
    case GL_DRAW_BUFFER9:
    case GL_DRAW_BUFFER10:
    case GL_DRAW_BUFFER11:
    case GL_DRAW_BUFFER12:
    case GL_DRAW_BUFFER13:
    case GL_DRAW_BUFFER14:
    case GL_DRAW_BUFFER15:
    case GL_DRAW_FRAMEBUFFER_BINDING:
    case GL_FRAGMENT_SHADER_DERIVATIVE_HINT:
    case GL_PACK_ROW_LENGTH:
    case GL_PRIMITIVE_RESTART_FIXED_INDEX:
    case GL_PROGRAM_BINARY_FORMATS:
    case GL_RASTERIZER_DISCARD:
    case GL_READ_BUFFER:
    case GL_READ_FRAMEBUFFER_BINDING:
    case GL_SAMPLER_BINDING:
    case GL_TEXTURE_BINDING_2D_ARRAY:
    case GL_TEXTURE_BINDING_3D:
    case GL_TRANSFORM_FEEDBACK_BINDING:
    case GL_TRANSFORM_FEEDBACK_ACTIVE:
    case GL_TRANSFORM_FEEDBACK_PAUSED:
    case GL_TRANSFORM_FEEDBACK_BUFFER_SIZE:
    case GL_TRANSFORM_FEEDBACK_BUFFER_START:
    case GL_UNIFORM_BUFFER_SIZE:
    case GL_UNIFORM_BUFFER_START:
    case GL_UNPACK_IMAGE_HEIGHT:
    case GL_UNPACK_ROW_LENGTH:
    case GL_VERTEX_ARRAY_BINDING:
      return false;
    default:
      return false;
  }
}

bool GLES2Implementation::GetBooleanvHelper(GLenum pname, GLboolean* params) {
  // TODO(gman): Make this handle pnames that return more than 1 value.
  GLint value;
  if (!GetHelper(pname, &value)) {
    return false;
  }
  *params = static_cast<GLboolean>(value);
  return true;
}

bool GLES2Implementation::GetFloatvHelper(GLenum pname, GLfloat* params) {
  // TODO(gman): Make this handle pnames that return more than 1 value.
  switch (pname) {
    case GL_MAX_TEXTURE_LOD_BIAS:
      *params = capabilities_.max_texture_lod_bias;
      return true;
    default:
      break;
  }
  GLint value;
  if (!GetHelper(pname, &value)) {
    return false;
  }
  *params = static_cast<GLfloat>(value);
  return true;
}

bool GLES2Implementation::GetInteger64vHelper(GLenum pname, GLint64* params) {
  switch (pname) {
    case GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS:
      *params = capabilities_.max_combined_fragment_uniform_components;
      return true;
    case GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS:
      *params = capabilities_.max_combined_vertex_uniform_components;
      return true;
    case GL_MAX_ELEMENT_INDEX:
      *params = capabilities_.max_element_index;
      return true;
    case GL_MAX_SERVER_WAIT_TIMEOUT:
      *params = capabilities_.max_server_wait_timeout;
      return true;
    case GL_MAX_UNIFORM_BLOCK_SIZE:
      *params = capabilities_.max_uniform_block_size;
      return true;
    case GL_TIMESTAMP_EXT:
      // We convert all GPU timestamps to CPU time.
      *params = (base::TimeTicks::Now() - base::TimeTicks()).InMicroseconds()
                * base::Time::kNanosecondsPerMicrosecond;
      return true;
    default:
      break;
  }
  GLint value;
  if (!GetHelper(pname, &value)) {
    return false;
  }
  *params = static_cast<GLint64>(value);
  return true;
}

bool GLES2Implementation::GetIntegervHelper(GLenum pname, GLint* params) {
  return GetHelper(pname, params);
}

bool GLES2Implementation::GetIntegeri_vHelper(
    GLenum pname, GLuint index, GLint* data) {
  // TODO(zmo): Implement client side caching.
  return false;
}

bool GLES2Implementation::GetInteger64i_vHelper(
    GLenum pname, GLuint index, GLint64* data) {
  // TODO(zmo): Implement client side caching.
  return false;
}

bool GLES2Implementation::GetInternalformativHelper(
    GLenum target, GLenum format, GLenum pname, GLsizei bufSize,
    GLint* params) {
  // TODO(zmo): Implement the client side caching.
  return false;
}

bool GLES2Implementation::GetSyncivHelper(
    GLsync sync, GLenum pname, GLsizei bufsize, GLsizei* length,
    GLint* values) {
  GLint value = 0;
  switch (pname) {
    case GL_OBJECT_TYPE:
      value = GL_SYNC_FENCE;
      break;
    case GL_SYNC_CONDITION:
      value = GL_SYNC_GPU_COMMANDS_COMPLETE;
      break;
    case GL_SYNC_FLAGS:
      value = 0;
      break;
    default:
      return false;
  }
  if (bufsize > 0) {
    DCHECK(values);
    *values = value;
  }
  if (length) {
    *length = 1;
  }
  return true;
}

bool GLES2Implementation::GetQueryObjectValueHelper(
    const char* function_name, GLuint id, GLenum pname, GLuint64* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] GetQueryObjectValueHelper("
                 << id << ", "
                 << GLES2Util::GetStringQueryObjectParameter(pname) << ", "
                 << static_cast<const void*>(params) << ")");

  QueryTracker::Query* query = query_tracker_->GetQuery(id);
  if (!query) {
    SetGLError(GL_INVALID_OPERATION,
               function_name, "unknown query id");
    return false;
  }

  if (query->Active()) {
    SetGLError(
        GL_INVALID_OPERATION,
        function_name,
        "query active. Did you call glEndQueryEXT?");
    return false;
  }

  if (query->NeverUsed()) {
    SetGLError(
        GL_INVALID_OPERATION,
        function_name, "Never used. Did you call glBeginQueryEXT?");
    return false;
  }

  bool valid_value = false;
  switch (pname) {
    case GL_QUERY_RESULT_EXT:
      if (!query->CheckResultsAvailable(helper_)) {
        helper_->WaitForToken(query->token());
        if (!query->CheckResultsAvailable(helper_)) {
          FinishHelper();
          CHECK(query->CheckResultsAvailable(helper_));
        }
      }
      *params = query->GetResult();
      valid_value = true;
      break;
    case GL_QUERY_RESULT_AVAILABLE_EXT:
      *params = query->CheckResultsAvailable(helper_);
      valid_value = true;
      break;
    default:
      SetGLErrorInvalidEnum(function_name, pname, "pname");
      break;
  }
  GPU_CLIENT_LOG("  " << *params);
  CheckGLError();
  return valid_value;
}

GLuint GLES2Implementation::GetMaxValueInBufferCHROMIUMHelper(
    GLuint buffer_id, GLsizei count, GLenum type, GLuint offset) {
  typedef cmds::GetMaxValueInBufferCHROMIUM::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return 0;
  }
  *result = 0;
  helper_->GetMaxValueInBufferCHROMIUM(
      buffer_id, count, type, offset, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  return *result;
}

GLuint GLES2Implementation::GetMaxValueInBufferCHROMIUM(
    GLuint buffer_id, GLsizei count, GLenum type, GLuint offset) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetMaxValueInBufferCHROMIUM("
                 << buffer_id << ", " << count << ", "
                 << GLES2Util::GetStringGetMaxIndexType(type)
                 << ", " << offset << ")");
  GLuint result = GetMaxValueInBufferCHROMIUMHelper(
      buffer_id, count, type, offset);
  GPU_CLIENT_LOG("returned " << result);
  CheckGLError();
  return result;
}

void GLES2Implementation::RestoreElementAndArrayBuffers(bool restore) {
  if (restore) {
    RestoreArrayBuffer(restore);
    // Restore the element array binding.
    // We only need to restore it if it wasn't a client side array.
    if (vertex_array_object_manager_->bound_element_array_buffer() == 0) {
      helper_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    }
  }
}

void GLES2Implementation::RestoreArrayBuffer(bool restore) {
  if (restore) {
    // Restore the user's current binding.
    helper_->BindBuffer(GL_ARRAY_BUFFER, bound_array_buffer_);
  }
}

void GLES2Implementation::DrawElements(
    GLenum mode, GLsizei count, GLenum type, const void* indices) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDrawElements("
      << GLES2Util::GetStringDrawMode(mode) << ", "
      << count << ", "
      << GLES2Util::GetStringIndexType(type) << ", "
      << static_cast<const void*>(indices) << ")");
  DrawElementsImpl(mode, count, type, indices, "glDrawElements");
}

void GLES2Implementation::DrawRangeElements(
    GLenum mode, GLuint start, GLuint end,
    GLsizei count, GLenum type, const void* indices) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDrawRangeElements("
      << GLES2Util::GetStringDrawMode(mode) << ", "
      << start << ", " << end << ", " << count << ", "
      << GLES2Util::GetStringIndexType(type) << ", "
      << static_cast<const void*>(indices) << ")");
  if (end < start) {
    SetGLError(GL_INVALID_VALUE, "glDrawRangeElements", "end < start");
    return;
  }
  DrawElementsImpl(mode, count, type, indices, "glDrawRangeElements");
}

void GLES2Implementation::DrawElementsImpl(
    GLenum mode, GLsizei count, GLenum type, const void* indices,
    const char* func_name) {
  if (count < 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "count < 0");
    return;
  }
  bool simulated = false;
  GLuint offset = ToGLuint(indices);
  if (count > 0) {
    if (vertex_array_object_manager_->bound_element_array_buffer() != 0 &&
        !ValidateOffset(func_name, reinterpret_cast<GLintptr>(indices))) {
      return;
    }
    if (!vertex_array_object_manager_->SetupSimulatedIndexAndClientSideBuffers(
        func_name, this, helper_, count, type, 0, indices,
        &offset, &simulated)) {
      return;
    }
  }
  helper_->DrawElements(mode, count, type, offset);
  RestoreElementAndArrayBuffers(simulated);
  CheckGLError();
}

void GLES2Implementation::Flush() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glFlush()");
  flush_id_ = GenerateNextFlushId();
  // Insert the cmd to call glFlush
  helper_->Flush();
  FlushHelper();
}

void GLES2Implementation::IssueShallowFlush() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glShallowFlushCHROMIUM()");
  flush_id_ = GenerateNextFlushId();
  FlushHelper();
}

void GLES2Implementation::ShallowFlushCHROMIUM() {
  IssueShallowFlush();
}

void GLES2Implementation::FlushHelper() {
  // Flush our command buffer
  // (tell the service to execute up to the flush cmd.)
  helper_->CommandBufferHelper::Flush();

  if (aggressively_free_resources_)
    FreeEverything();
}

void GLES2Implementation::OrderingBarrierCHROMIUM() {
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glOrderingBarrierCHROMIUM");
  // Flush command buffer at the GPU channel level.  May be implemented as
  // Flush().
  helper_->CommandBufferHelper::OrderingBarrier();
}

void GLES2Implementation::Finish() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  flush_id_ = GenerateNextFlushId();
  FinishHelper();
}

void GLES2Implementation::ShallowFinishCHROMIUM() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  TRACE_EVENT0("gpu", "GLES2::ShallowFinishCHROMIUM");
  flush_id_ = GenerateNextFlushId();
  // Flush our command buffer (tell the service to execute up to the flush cmd
  // and don't return until it completes).
  helper_->CommandBufferHelper::Finish();

  if (aggressively_free_resources_)
    FreeEverything();
}

void GLES2Implementation::FinishHelper() {
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glFinish()");
  TRACE_EVENT0("gpu", "GLES2::Finish");
  // Insert the cmd to call glFinish
  helper_->Finish();
  // Finish our command buffer
  // (tell the service to execute up to the Finish cmd and wait for it to
  // execute.)
  helper_->CommandBufferHelper::Finish();

  if (aggressively_free_resources_)
    FreeEverything();
}

GLuint GLES2Implementation::GetLastFlushIdCHROMIUM() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetLastFlushIdCHROMIUM()");
  return flush_id_;
}

void GLES2Implementation::SwapBuffers(uint64_t swap_id, GLbitfield flags) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glSwapBuffers()");
  // TODO(piman): Strictly speaking we'd want to insert the token after the
  // swap, but the state update with the updated token might not have happened
  // by the time the SwapBuffer callback gets called, forcing us to synchronize
  // with the GPU process more than needed. So instead, make it happen before.
  // All it means is that we could be slightly looser on the kMaxSwapBuffers
  // semantics if the client doesn't use the callback mechanism, and by chance
  // the scheduler yields between the InsertToken and the SwapBuffers.
  swap_buffers_tokens_.push(helper_->InsertToken());
  helper_->SwapBuffers(swap_id, flags);
  helper_->CommandBufferHelper::Flush();
  // Wait if we added too many swap buffers. Add 1 to kMaxSwapBuffers to
  // compensate for TODO above.
  if (swap_buffers_tokens_.size() > kMaxSwapBuffers + 1) {
    helper_->WaitForToken(swap_buffers_tokens_.front());
    swap_buffers_tokens_.pop();
  }
}

void GLES2Implementation::SwapBuffersWithBoundsCHROMIUM(uint64_t swap_id,
                                                        GLsizei count,
                                                        const GLint* rects,
                                                        GLbitfield flags) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glSwapBuffersWithBoundsCHROMIUM("
                     << count << ", " << static_cast<const void*>(rects)
                     << ")");
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (GLsizei i = 0; i < count; ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << rects[0 + i * 4] << ", "
                          << rects[1 + i * 4] << ", " << rects[2 + i * 4]
                          << ", " << rects[3 + i * 4]);
    }
  });
  if (count < 0) {
    SetGLError(GL_INVALID_VALUE, "glSwapBuffersWithBoundsCHROMIUM",
               "count < 0");
    return;
  }

  // Same flow control as GLES2Implementation::SwapBuffers (see comments there).
  swap_buffers_tokens_.push(helper_->InsertToken());
  helper_->SwapBuffersWithBoundsCHROMIUMImmediate(swap_id, count, rects, flags);
  helper_->CommandBufferHelper::Flush();
  if (swap_buffers_tokens_.size() > kMaxSwapBuffers + 1) {
    helper_->WaitForToken(swap_buffers_tokens_.front());
    swap_buffers_tokens_.pop();
  }
}

void GLES2Implementation::BindAttribLocation(
  GLuint program, GLuint index, const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glBindAttribLocation("
      << program << ", " << index << ", " << name << ")");
  SetBucketAsString(kResultBucketId, name);
  helper_->BindAttribLocationBucket(program, index, kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);
  CheckGLError();
}

void GLES2Implementation::BindFragDataLocationEXT(GLuint program,
                                                  GLuint colorName,
                                                  const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glBindFragDataLocationEXT("
                     << program << ", " << colorName << ", " << name << ")");
  SetBucketAsString(kResultBucketId, name);
  helper_->BindFragDataLocationEXTBucket(program, colorName, kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);
  CheckGLError();
}

void GLES2Implementation::BindFragDataLocationIndexedEXT(GLuint program,
                                                         GLuint colorName,
                                                         GLuint index,
                                                         const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glBindFragDataLocationEXT("
                     << program << ", " << colorName << ", " << index << ", "
                     << name << ")");
  SetBucketAsString(kResultBucketId, name);
  helper_->BindFragDataLocationIndexedEXTBucket(program, colorName, index,
                                                kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);
  CheckGLError();
}

void GLES2Implementation::BindUniformLocationCHROMIUM(
  GLuint program, GLint location, const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glBindUniformLocationCHROMIUM("
      << program << ", " << location << ", " << name << ")");
  SetBucketAsString(kResultBucketId, name);
  helper_->BindUniformLocationCHROMIUMBucket(
      program, location, kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);
  CheckGLError();
}

void GLES2Implementation::GetVertexAttribPointerv(
    GLuint index, GLenum pname, void** ptr) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetVertexAttribPointer("
      << index << ", " << GLES2Util::GetStringVertexPointer(pname) << ", "
      << static_cast<void*>(ptr) << ")");
  GPU_CLIENT_LOG_CODE_BLOCK(int32_t num_results = 1);
  if (!vertex_array_object_manager_->GetAttribPointer(index, pname, ptr)) {
    TRACE_EVENT0("gpu", "GLES2::GetVertexAttribPointerv");
    typedef cmds::GetVertexAttribPointerv::Result Result;
    Result* result = GetResultAs<Result*>();
    if (!result) {
      return;
    }
    result->SetNumResults(0);
    helper_->GetVertexAttribPointerv(
      index, pname, GetResultShmId(), GetResultShmOffset());
    WaitForCmd();
    result->CopyResult(ptr);
    GPU_CLIENT_LOG_CODE_BLOCK(num_results = result->GetNumResults());
  }
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < num_results; ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << ptr[i]);
    }
  });
  CheckGLError();
}

bool GLES2Implementation::DeleteProgramHelper(GLuint program) {
  if (!GetIdHandler(SharedIdNamespaces::kProgramsAndShaders)
           ->FreeIds(this, 1, &program,
                     &GLES2Implementation::DeleteProgramStub)) {
    SetGLError(
        GL_INVALID_VALUE,
        "glDeleteProgram", "id not created by this context.");
    return false;
  }
  if (program == current_program_) {
    current_program_ = 0;
  }
  return true;
}

void GLES2Implementation::DeleteProgramStub(
    GLsizei n, const GLuint* programs) {
  DCHECK_EQ(1, n);
  share_group_->program_info_manager()->DeleteInfo(programs[0]);
  helper_->DeleteProgram(programs[0]);
}

bool GLES2Implementation::DeleteShaderHelper(GLuint shader) {
  if (!GetIdHandler(SharedIdNamespaces::kProgramsAndShaders)
           ->FreeIds(this, 1, &shader,
                     &GLES2Implementation::DeleteShaderStub)) {
    SetGLError(
        GL_INVALID_VALUE,
        "glDeleteShader", "id not created by this context.");
    return false;
  }
  return true;
}

void GLES2Implementation::DeleteShaderStub(
    GLsizei n, const GLuint* shaders) {
  DCHECK_EQ(1, n);
  share_group_->program_info_manager()->DeleteInfo(shaders[0]);
  helper_->DeleteShader(shaders[0]);
}

void GLES2Implementation::DeleteSyncHelper(GLsync sync) {
  GLuint sync_uint = ToGLuint(sync);
  if (!GetIdHandler(SharedIdNamespaces::kSyncs)
           ->FreeIds(this, 1, &sync_uint,
                     &GLES2Implementation::DeleteSyncStub)) {
    SetGLError(
        GL_INVALID_VALUE,
        "glDeleteSync", "id not created by this context.");
  }
}

void GLES2Implementation::DeleteSyncStub(GLsizei n, const GLuint* syncs) {
  DCHECK_EQ(1, n);
  helper_->DeleteSync(syncs[0]);
}

GLint GLES2Implementation::GetAttribLocationHelper(
    GLuint program, const char* name) {
  typedef cmds::GetAttribLocation::Result Result;
  SetBucketAsCString(kResultBucketId, name);
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return -1;
  }
  *result = -1;
  helper_->GetAttribLocation(
      program, kResultBucketId, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  helper_->SetBucketSize(kResultBucketId, 0);
  return *result;
}

GLint GLES2Implementation::GetAttribLocation(
    GLuint program, const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetAttribLocation(" << program
      << ", " << name << ")");
  TRACE_EVENT0("gpu", "GLES2::GetAttribLocation");
  GLint loc = share_group_->program_info_manager()->GetAttribLocation(
      this, program, name);
  GPU_CLIENT_LOG("returned " << loc);
  CheckGLError();
  return loc;
}

GLint GLES2Implementation::GetUniformLocationHelper(
    GLuint program, const char* name) {
  typedef cmds::GetUniformLocation::Result Result;
  SetBucketAsCString(kResultBucketId, name);
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return -1;
  }
  *result = -1;
  helper_->GetUniformLocation(program, kResultBucketId,
                                    GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  helper_->SetBucketSize(kResultBucketId, 0);
  return *result;
}

GLint GLES2Implementation::GetUniformLocation(
    GLuint program, const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetUniformLocation(" << program
      << ", " << name << ")");
  TRACE_EVENT0("gpu", "GLES2::GetUniformLocation");
  GLint loc = share_group_->program_info_manager()->GetUniformLocation(
      this, program, name);
  GPU_CLIENT_LOG("returned " << loc);
  CheckGLError();
  return loc;
}

bool GLES2Implementation::GetUniformIndicesHelper(
    GLuint program, GLsizei count, const char* const* names, GLuint* indices) {
  typedef cmds::GetUniformIndices::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  result->SetNumResults(0);
  if (!PackStringsToBucket(count, names, NULL, "glGetUniformIndices")) {
    return false;
  }
  helper_->GetUniformIndices(program, kResultBucketId,
                             GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  if (result->GetNumResults() != count) {
    return false;
  }
  result->CopyResult(indices);
  return true;
}

void GLES2Implementation::GetUniformIndices(
    GLuint program, GLsizei count, const char* const* names, GLuint* indices) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetUniformIndices(" << program
      << ", " << count << ", " << names << ", " << indices << ")");
  TRACE_EVENT0("gpu", "GLES2::GetUniformIndices");
  if (count < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetUniformIndices", "count < 0");
    return;
  }
  if (count == 0) {
    return;
  }
  bool success = share_group_->program_info_manager()->GetUniformIndices(
      this, program, count, names, indices);
  if (success) {
    GPU_CLIENT_LOG_CODE_BLOCK({
      for (GLsizei ii = 0; ii < count; ++ii) {
        GPU_CLIENT_LOG("  " << ii << ": " << indices[ii]);
      }
    });
  }
  CheckGLError();
}

bool GLES2Implementation::GetProgramivHelper(
    GLuint program, GLenum pname, GLint* params) {
  bool got_value = share_group_->program_info_manager()->GetProgramiv(
      this, program, pname, params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    if (got_value) {
      GPU_CLIENT_LOG("  0: " << *params);
    }
  });
  return got_value;
}

GLint GLES2Implementation::GetFragDataIndexEXTHelper(GLuint program,
                                                     const char* name) {
  typedef cmds::GetFragDataIndexEXT::Result Result;
  SetBucketAsCString(kResultBucketId, name);
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return -1;
  }
  *result = -1;
  helper_->GetFragDataIndexEXT(program, kResultBucketId, GetResultShmId(),
                               GetResultShmOffset());
  WaitForCmd();
  helper_->SetBucketSize(kResultBucketId, 0);
  return *result;
}

GLint GLES2Implementation::GetFragDataIndexEXT(GLuint program,
                                               const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetFragDataIndexEXT(" << program
                     << ", " << name << ")");
  TRACE_EVENT0("gpu", "GLES2::GetFragDataIndexEXT");
  GLint loc = share_group_->program_info_manager()->GetFragDataIndex(
      this, program, name);
  GPU_CLIENT_LOG("returned " << loc);
  CheckGLError();
  return loc;
}

GLint GLES2Implementation::GetFragDataLocationHelper(
    GLuint program, const char* name) {
  typedef cmds::GetFragDataLocation::Result Result;
  SetBucketAsCString(kResultBucketId, name);
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return -1;
  }
  *result = -1;
  helper_->GetFragDataLocation(
      program, kResultBucketId, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  helper_->SetBucketSize(kResultBucketId, 0);
  return *result;
}

GLint GLES2Implementation::GetFragDataLocation(
    GLuint program, const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetFragDataLocation("
      << program << ", " << name << ")");
  TRACE_EVENT0("gpu", "GLES2::GetFragDataLocation");
  GLint loc = share_group_->program_info_manager()->GetFragDataLocation(
      this, program, name);
  GPU_CLIENT_LOG("returned " << loc);
  CheckGLError();
  return loc;
}

GLuint GLES2Implementation::GetUniformBlockIndexHelper(
    GLuint program, const char* name) {
  typedef cmds::GetUniformBlockIndex::Result Result;
  SetBucketAsCString(kResultBucketId, name);
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return GL_INVALID_INDEX;
  }
  *result = GL_INVALID_INDEX;
  helper_->GetUniformBlockIndex(
      program, kResultBucketId, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  helper_->SetBucketSize(kResultBucketId, 0);
  return *result;
}

GLuint GLES2Implementation::GetUniformBlockIndex(
    GLuint program, const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetUniformBlockIndex("
      << program << ", " << name << ")");
  TRACE_EVENT0("gpu", "GLES2::GetUniformBlockIndex");
  GLuint index = share_group_->program_info_manager()->GetUniformBlockIndex(
      this, program, name);
  GPU_CLIENT_LOG("returned " << index);
  CheckGLError();
  return index;
}

void GLES2Implementation::LinkProgram(GLuint program) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glLinkProgram(" << program << ")");
  helper_->LinkProgram(program);
  share_group_->program_info_manager()->CreateInfo(program);
  CheckGLError();
}

void GLES2Implementation::ShaderBinary(
    GLsizei n, const GLuint* shaders, GLenum binaryformat, const void* binary,
    GLsizei length) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glShaderBinary(" << n << ", "
      << static_cast<const void*>(shaders) << ", "
      << GLES2Util::GetStringEnum(binaryformat) << ", "
      << static_cast<const void*>(binary) << ", "
      << length << ")");
  if (n < 0) {
    SetGLError(GL_INVALID_VALUE, "glShaderBinary", "n < 0.");
    return;
  }
  if (length < 0) {
    SetGLError(GL_INVALID_VALUE, "glShaderBinary", "length < 0.");
    return;
  }
  // TODO(gman): ShaderBinary should use buckets.
  unsigned int shader_id_size = n * sizeof(*shaders);
  ScopedTransferBufferArray<GLint> buffer(
      shader_id_size + length, helper_, transfer_buffer_);
  if (!buffer.valid() || buffer.num_elements() != shader_id_size + length) {
    SetGLError(GL_OUT_OF_MEMORY, "glShaderBinary", "out of memory.");
    return;
  }
  void* shader_ids = buffer.elements();
  void* shader_data = buffer.elements() + shader_id_size;
  memcpy(shader_ids, shaders, shader_id_size);
  memcpy(shader_data, binary, length);
  helper_->ShaderBinary(
      n,
      buffer.shm_id(),
      buffer.offset(),
      binaryformat,
      buffer.shm_id(),
      buffer.offset() + shader_id_size,
      length);
  CheckGLError();
}

void GLES2Implementation::PixelStorei(GLenum pname, GLint param) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glPixelStorei("
      << GLES2Util::GetStringPixelStore(pname) << ", "
      << param << ")");
  // We have to validate before caching these parameters because we use them
  // to compute image sizes on the client side.
  switch (pname) {
    case GL_PACK_ALIGNMENT:
    case GL_UNPACK_ALIGNMENT:
      if (param != 1 && param != 2 && param != 4 && param != 8) {
        SetGLError(GL_INVALID_VALUE, "glPixelStorei", "invalid param");
        return;
      }
      break;
    case GL_PACK_ROW_LENGTH:
    case GL_PACK_SKIP_PIXELS:
    case GL_PACK_SKIP_ROWS:
    case GL_UNPACK_IMAGE_HEIGHT:
    case GL_UNPACK_SKIP_IMAGES:
      if (capabilities_.major_version < 3) {
        SetGLError(GL_INVALID_ENUM, "glPixelStorei", "invalid pname");
        return;
      }
      if (param < 0) {
        SetGLError(GL_INVALID_VALUE, "glPixelStorei", "invalid param");
        return;
      }
      break;
    case GL_UNPACK_ROW_LENGTH:
    case GL_UNPACK_SKIP_ROWS:
    case GL_UNPACK_SKIP_PIXELS:
      // These parameters are always enabled in ES2 by EXT_unpack_subimage.
      if (param < 0) {
        SetGLError(GL_INVALID_VALUE, "glPixelStorei", "invalid param");
        return;
      }
      break;
    default:
      SetGLError(GL_INVALID_ENUM, "glPixelStorei", "invalid pname");
      return;
  }
  // Do not send SKIP parameters to the service side.
  // Handle them on the client side.
  switch (pname) {
    case GL_PACK_ALIGNMENT:
      pack_alignment_ = param;
      break;
    case GL_PACK_ROW_LENGTH:
      pack_row_length_ = param;
      break;
    case GL_PACK_SKIP_PIXELS:
      pack_skip_pixels_ = param;
      return;
    case GL_PACK_SKIP_ROWS:
      pack_skip_rows_ = param;
      return;
    case GL_UNPACK_ALIGNMENT:
      unpack_alignment_ = param;
      break;
    case GL_UNPACK_ROW_LENGTH:
      unpack_row_length_ = param;
      if (capabilities_.major_version < 3) {
        // In ES2 with EXT_unpack_subimage, it's handled on the client side
        // and there is no need to send it to the service side.
        return;
      }
      break;
    case GL_UNPACK_IMAGE_HEIGHT:
      unpack_image_height_ = param;
      break;
    case GL_UNPACK_SKIP_ROWS:
      unpack_skip_rows_ = param;
      return;
    case GL_UNPACK_SKIP_PIXELS:
      unpack_skip_pixels_ = param;
      return;
    case GL_UNPACK_SKIP_IMAGES:
      unpack_skip_images_ = param;
      return;
    default:
      NOTREACHED();
      break;
  }
  helper_->PixelStorei(pname, param);
  CheckGLError();
}

void GLES2Implementation::VertexAttribIPointer(
    GLuint index, GLint size, GLenum type, GLsizei stride, const void* ptr) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glVertexAttribIPointer("
      << index << ", "
      << size << ", "
      << GLES2Util::GetStringVertexAttribIType(type) << ", "
      << stride << ", "
      << ptr << ")");
  // Record the info on the client side.
  if (!vertex_array_object_manager_->SetAttribPointer(bound_array_buffer_,
                                                      index,
                                                      size,
                                                      type,
                                                      GL_FALSE,
                                                      stride,
                                                      ptr,
                                                      GL_TRUE)) {
    SetGLError(GL_INVALID_OPERATION, "glVertexAttribIPointer",
               "client side arrays are not allowed in vertex array objects.");
    return;
  }
  if (!support_client_side_arrays_ || bound_array_buffer_ != 0) {
    // Only report NON client side buffers to the service.
    if (!ValidateOffset("glVertexAttribIPointer",
                        reinterpret_cast<GLintptr>(ptr))) {
      return;
    }
    helper_->VertexAttribIPointer(index, size, type, stride, ToGLuint(ptr));
  }
  CheckGLError();
}

void GLES2Implementation::VertexAttribPointer(
    GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride,
    const void* ptr) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glVertexAttribPointer("
      << index << ", "
      << size << ", "
      << GLES2Util::GetStringVertexAttribType(type) << ", "
      << GLES2Util::GetStringBool(normalized) << ", "
      << stride << ", "
      << ptr << ")");
  // Record the info on the client side.
  if (!vertex_array_object_manager_->SetAttribPointer(bound_array_buffer_,
                                                      index,
                                                      size,
                                                      type,
                                                      normalized,
                                                      stride,
                                                      ptr,
                                                      GL_FALSE)) {
    SetGLError(GL_INVALID_OPERATION, "glVertexAttribPointer",
               "client side arrays are not allowed in vertex array objects.");
    return;
  }
  if (!support_client_side_arrays_ || bound_array_buffer_ != 0) {
    // Only report NON client side buffers to the service.
    if (!ValidateOffset("glVertexAttribPointer",
                        reinterpret_cast<GLintptr>(ptr))) {
      return;
    }
    helper_->VertexAttribPointer(index, size, type, normalized, stride,
                                 ToGLuint(ptr));
  }
  CheckGLError();
}

void GLES2Implementation::VertexAttribDivisorANGLE(
    GLuint index, GLuint divisor) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glVertexAttribDivisorANGLE("
      << index << ", "
      << divisor << ") ");
  // Record the info on the client side.
  vertex_array_object_manager_->SetAttribDivisor(index, divisor);
  helper_->VertexAttribDivisorANGLE(index, divisor);
  CheckGLError();
}

void GLES2Implementation::BufferDataHelper(
    GLenum target, GLsizeiptr size, const void* data, GLenum usage) {
  if (!ValidateSize("glBufferData", size))
    return;

#if defined(MEMORY_SANITIZER) && !defined(OS_NACL)
  // Do not upload uninitialized data. Even if it's not a bug, it can cause a
  // bogus MSan report during a readback later. This is because MSan doesn't
  // understand shared memory and would assume we were reading back the same
  // unintialized data.
  if (data) __msan_check_mem_is_initialized(data, size);
#endif

  GLuint buffer_id;
  if (GetBoundPixelTransferBuffer(target, "glBufferData", &buffer_id)) {
    if (!buffer_id) {
      return;
    }

    BufferTracker::Buffer* buffer = buffer_tracker_->GetBuffer(buffer_id);
    if (buffer)
      RemoveTransferBuffer(buffer);

    // Create new buffer.
    buffer = buffer_tracker_->CreateBuffer(buffer_id, size);
    DCHECK(buffer);
    if (buffer->address() && data)
      memcpy(buffer->address(), data, size);
    return;
  }

  if (IsReadbackUsage(usage)) {
    GLuint id = GetBoundBufferHelper(target);
    readback_buffer_shadow_tracker_->GetOrCreateBuffer(id, size);
  }

  RemoveMappedBufferRangeByTarget(target);

  // If there is no data just send BufferData
  if (size == 0 || !data) {
    helper_->BufferData(target, size, 0, 0, usage);
    return;
  }

  // See if we can send all at once.
  ScopedTransferBufferPtr buffer(size, helper_, transfer_buffer_);
  if (!buffer.valid()) {
    return;
  }

  if (buffer.size() >= static_cast<unsigned int>(size)) {
    memcpy(buffer.address(), data, size);
    helper_->BufferData(
        target,
        size,
        buffer.shm_id(),
        buffer.offset(),
        usage);
    return;
  }

  // Make the buffer with BufferData then send via BufferSubData
  helper_->BufferData(target, size, 0, 0, usage);
  BufferSubDataHelperImpl(target, 0, size, data, &buffer);
  CheckGLError();
}

void GLES2Implementation::BufferData(
    GLenum target, GLsizeiptr size, const void* data, GLenum usage) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glBufferData("
      << GLES2Util::GetStringBufferTarget(target) << ", "
      << size << ", "
      << static_cast<const void*>(data) << ", "
      << GLES2Util::GetStringBufferUsage(usage) << ")");
  BufferDataHelper(target, size, data, usage);
  CheckGLError();
}

void GLES2Implementation::BufferSubDataHelper(
    GLenum target, GLintptr offset, GLsizeiptr size, const void* data) {
  if (size == 0) {
    return;
  }

  if (!ValidateSize("glBufferSubData", size) ||
      !ValidateOffset("glBufferSubData", offset)) {
    return;
  }

  GLuint buffer_id;
  if (GetBoundPixelTransferBuffer(target, "glBufferSubData", &buffer_id)) {
    if (!buffer_id) {
      return;
    }
    BufferTracker::Buffer* buffer = buffer_tracker_->GetBuffer(buffer_id);
    if (!buffer) {
      SetGLError(GL_INVALID_VALUE, "glBufferSubData", "unknown buffer");
      return;
    }

    int32_t end = 0;
    int32_t buffer_size = buffer->size();
    if (!SafeAddInt32(offset, size, &end) || end > buffer_size) {
      SetGLError(GL_INVALID_VALUE, "glBufferSubData", "out of range");
      return;
    }

    if (buffer->address() && data)
      memcpy(static_cast<uint8_t*>(buffer->address()) + offset, data, size);
    return;
  }

  ScopedTransferBufferPtr buffer(size, helper_, transfer_buffer_);
  BufferSubDataHelperImpl(target, offset, size, data, &buffer);
}

void GLES2Implementation::BufferSubDataHelperImpl(
    GLenum target, GLintptr offset, GLsizeiptr size, const void* data,
    ScopedTransferBufferPtr* buffer) {
  DCHECK(buffer);
  DCHECK_GT(size, 0);

  const int8_t* source = static_cast<const int8_t*>(data);
  while (size) {
    if (!buffer->valid() || buffer->size() == 0) {
      buffer->Reset(size);
      if (!buffer->valid()) {
        return;
      }
    }
    memcpy(buffer->address(), source, buffer->size());
    helper_->BufferSubData(
        target, offset, buffer->size(), buffer->shm_id(), buffer->offset());
    InvalidateReadbackBufferShadowDataCHROMIUM(GetBoundBufferHelper(target));
    offset += buffer->size();
    source += buffer->size();
    size -= buffer->size();
    buffer->Release();
  }
}

void GLES2Implementation::BufferSubData(
    GLenum target, GLintptr offset, GLsizeiptr size, const void* data) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glBufferSubData("
      << GLES2Util::GetStringBufferTarget(target) << ", "
      << offset << ", " << size << ", "
      << static_cast<const void*>(data) << ")");
  BufferSubDataHelper(target, offset, size, data);
  CheckGLError();
}

void GLES2Implementation::RemoveTransferBuffer(BufferTracker::Buffer* buffer) {
  int32_t token = buffer->last_usage_token();

  if (token) {
    if (helper_->HasTokenPassed(token))
      buffer_tracker_->Free(buffer);
    else
      buffer_tracker_->FreePendingToken(buffer, token);
  } else {
      buffer_tracker_->Free(buffer);
  }

  buffer_tracker_->RemoveBuffer(buffer->id());
}

bool GLES2Implementation::GetBoundPixelTransferBuffer(
    GLenum target,
    const char* function_name,
    GLuint* buffer_id) {
  *buffer_id = 0;

  switch (target) {
    case GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM:
      *buffer_id = bound_pixel_pack_transfer_buffer_id_;
      break;
    case GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM:
      *buffer_id = bound_pixel_unpack_transfer_buffer_id_;
      break;
    default:
      // Unknown target
      return false;
  }
  if (!*buffer_id) {
    SetGLError(GL_INVALID_OPERATION, function_name, "no buffer bound");
  }
  return true;
}

BufferTracker::Buffer* GLES2Implementation::GetBoundPixelTransferBufferIfValid(
    GLuint buffer_id, const char* function_name, GLuint offset, GLsizei size) {
  DCHECK(buffer_id);
  BufferTracker::Buffer* buffer = buffer_tracker_->GetBuffer(buffer_id);
  if (!buffer) {
    SetGLError(GL_INVALID_OPERATION, function_name, "invalid buffer");
    return nullptr;
  }
  if (buffer->mapped()) {
    SetGLError(GL_INVALID_OPERATION, function_name, "buffer mapped");
    return nullptr;
  }
  base::CheckedNumeric<uint32_t> buffer_offset = buffer->shm_offset();
  buffer_offset += offset;
  if (!buffer_offset.IsValid()) {
    SetGLError(GL_INVALID_VALUE, function_name, "offset to large");
    return nullptr;
  }
  base::CheckedNumeric<uint32_t> required_size = offset;
  required_size += size;
  if (!required_size.IsValid() ||
      buffer->size() < required_size.ValueOrDefault(0)) {
    SetGLError(GL_INVALID_VALUE, function_name, "unpack size to large");
    return nullptr;
  }
  return buffer;
}

void GLES2Implementation::InvalidateReadbackBufferShadowDataCHROMIUM(
    GLuint buffer_id) {
  readback_buffer_shadow_tracker_->OnBufferWrite(buffer_id);
}

void GLES2Implementation::CompressedTexImage2D(
    GLenum target, GLint level, GLenum internalformat, GLsizei width,
    GLsizei height, GLint border, GLsizei image_size, const void* data) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCompressedTexImage2D("
      << GLES2Util::GetStringTextureTarget(target) << ", "
      << level << ", "
      << GLES2Util::GetStringCompressedTextureFormat(internalformat) << ", "
      << width << ", " << height << ", " << border << ", "
      << image_size << ", "
      << static_cast<const void*>(data) << ")");
  if (width < 0 || height < 0 || level < 0) {
    SetGLError(GL_INVALID_VALUE, "glCompressedTexImage2D", "dimension < 0");
    return;
  }
  if (border != 0) {
    SetGLError(GL_INVALID_VALUE, "glCompressedTexImage2D", "border != 0");
    return;
  }
  // If there's a pixel unpack buffer bound use it when issuing
  // CompressedTexImage2D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    GLuint offset = ToGLuint(data);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_,
        "glCompressedTexImage2D", offset, image_size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->CompressedTexImage2D(
          target, level, internalformat, width, height, image_size,
          buffer->shm_id(), buffer->shm_offset() + offset);
      buffer->set_last_usage_token(helper_->InsertToken());
    }
    return;
  }
  if (bound_pixel_unpack_buffer_) {
    helper_->CompressedTexImage2D(target, level, internalformat, width, height,
                                  image_size, 0, ToGLuint(data));
  } else if (data) {
    SetBucketContents(kResultBucketId, data, image_size);
    helper_->CompressedTexImage2DBucket(target, level, internalformat, width,
                                        height, kResultBucketId);
    // Free the bucket. This is not required but it does free up the memory.
    // and we don't have to wait for the result so from the client's perspective
    // it's cheap.
    helper_->SetBucketSize(kResultBucketId, 0);
  } else {
    helper_->CompressedTexImage2D(target, level, internalformat, width, height,
                                  image_size, 0, 0);
  }
  CheckGLError();
}

void GLES2Implementation::CompressedTexSubImage2D(
    GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width,
    GLsizei height, GLenum format, GLsizei image_size, const void* data) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCompressedTexSubImage2D("
      << GLES2Util::GetStringTextureTarget(target) << ", "
      << level << ", "
      << xoffset << ", " << yoffset << ", "
      << width << ", " << height << ", "
      << GLES2Util::GetStringCompressedTextureFormat(format) << ", "
      << image_size << ", "
      << static_cast<const void*>(data) << ")");
  if (width < 0 || height < 0 || level < 0) {
    SetGLError(GL_INVALID_VALUE, "glCompressedTexSubImage2D", "dimension < 0");
    return;
  }
  // If there's a pixel unpack buffer bound use it when issuing
  // CompressedTexSubImage2D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    GLuint offset = ToGLuint(data);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_,
        "glCompressedTexSubImage2D", offset, image_size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->CompressedTexSubImage2D(
          target, level, xoffset, yoffset, width, height, format, image_size,
          buffer->shm_id(), buffer->shm_offset() + offset);
      buffer->set_last_usage_token(helper_->InsertToken());
      CheckGLError();
    }
    return;
  }
  if (bound_pixel_unpack_buffer_) {
    helper_->CompressedTexSubImage2D(
        target, level, xoffset, yoffset, width, height, format, image_size,
        0, ToGLuint(data));
  } else if (data) {
    SetBucketContents(kResultBucketId, data, image_size);
    helper_->CompressedTexSubImage2DBucket(
        target, level, xoffset, yoffset, width, height, format,
        kResultBucketId);
    // Free the bucket. This is not required but it does free up the memory.
    // and we don't have to wait for the result so from the client's perspective
    // it's cheap.
    helper_->SetBucketSize(kResultBucketId, 0);
  } else {
    helper_->CompressedTexSubImage2D(target, level, xoffset, yoffset, width,
                                     height, format, image_size, 0, 0);
  }
  CheckGLError();
}

void GLES2Implementation::CompressedTexImage3D(
    GLenum target, GLint level, GLenum internalformat, GLsizei width,
    GLsizei height, GLsizei depth, GLint border, GLsizei image_size,
    const void* data) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCompressedTexImage3D("
      << GLES2Util::GetStringTexture3DTarget(target) << ", " << level << ", "
      << GLES2Util::GetStringCompressedTextureFormat(internalformat) << ", "
      << width << ", " << height << ", " << depth << ", " << border << ", "
      << image_size << ", " << static_cast<const void*>(data) << ")");
  if (width < 0 || height < 0 || depth < 0 || level < 0) {
    SetGLError(GL_INVALID_VALUE, "glCompressedTexImage3D", "dimension < 0");
    return;
  }
  if (border != 0) {
    SetGLError(GL_INVALID_VALUE, "glCompressedTexImage3D", "border != 0");
    return;
  }
  // If there's a pixel unpack buffer bound use it when issuing
  // CompressedTexImage3D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    GLuint offset = ToGLuint(data);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_,
        "glCompressedTexImage3D", offset, image_size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->CompressedTexImage3D(
          target, level, internalformat, width, height, depth, image_size,
          buffer->shm_id(), buffer->shm_offset() + offset);
      buffer->set_last_usage_token(helper_->InsertToken());
    }
    return;
  }
  if (bound_pixel_unpack_buffer_) {
    helper_->CompressedTexImage3D(
        target, level, internalformat, width, height, depth, image_size,
        0, ToGLuint(data));
  } else if (data) {
    SetBucketContents(kResultBucketId, data, image_size);
    helper_->CompressedTexImage3DBucket(target, level, internalformat, width,
                                        height, depth, kResultBucketId);
    // Free the bucket. This is not required but it does free up the memory.
    // and we don't have to wait for the result so from the client's perspective
    // it's cheap.
    helper_->SetBucketSize(kResultBucketId, 0);
  } else {
    helper_->CompressedTexImage3D(target, level, internalformat, width, height,
                                  depth, image_size, 0, 0);
  }
  CheckGLError();
}

void GLES2Implementation::CompressedTexSubImage3D(
    GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint zoffset,
    GLsizei width, GLsizei height, GLsizei depth, GLenum format,
    GLsizei image_size, const void* data) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCompressedTexSubImage3D("
      << GLES2Util::GetStringTextureTarget(target) << ", "
      << level << ", "
      << xoffset << ", " << yoffset << ", " << zoffset << ", "
      << width << ", " << height << ", " << depth << ", "
      << GLES2Util::GetStringCompressedTextureFormat(format) << ", "
      << image_size << ", "
      << static_cast<const void*>(data) << ")");
  if (width < 0 || height < 0 || depth < 0 || level < 0) {
    SetGLError(GL_INVALID_VALUE, "glCompressedTexSubImage3D", "dimension < 0");
    return;
  }
  // If there's a pixel unpack buffer bound use it when issuing
  // CompressedTexSubImage3D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    GLuint offset = ToGLuint(data);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_,
        "glCompressedTexSubImage3D", offset, image_size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->CompressedTexSubImage3D(
          target, level, xoffset, yoffset, zoffset,
          width, height, depth, format, image_size,
          buffer->shm_id(), buffer->shm_offset() + offset);
      buffer->set_last_usage_token(helper_->InsertToken());
      CheckGLError();
    }
    return;
  }
  if (bound_pixel_unpack_buffer_) {
    helper_->CompressedTexSubImage3D(
        target, level, xoffset, yoffset, zoffset, width, height, depth, format,
        image_size, 0, ToGLuint(data));
  } else if (data) {
    SetBucketContents(kResultBucketId, data, image_size);
    helper_->CompressedTexSubImage3DBucket(
        target, level, xoffset, yoffset, zoffset, width, height, depth, format,
        kResultBucketId);
    // Free the bucket. This is not required but it does free up the memory.
    // and we don't have to wait for the result so from the client's perspective
    // it's cheap.
    helper_->SetBucketSize(kResultBucketId, 0);
  } else {
    helper_->CompressedTexSubImage3D(target, level, xoffset, yoffset, zoffset,
                                     width, height, depth, format, image_size,
                                     0, 0);
  }
  CheckGLError();
}

PixelStoreParams GLES2Implementation::GetUnpackParameters(Dimension dimension) {
  PixelStoreParams params;
  params.alignment = unpack_alignment_;
  params.row_length = unpack_row_length_;
  params.skip_pixels = unpack_skip_pixels_;
  params.skip_rows = unpack_skip_rows_;
  if (dimension == k3D) {
    params.image_height = unpack_image_height_;
    params.skip_images = unpack_skip_images_;
  }
  return params;
}

uint64_t GLES2Implementation::PrepareNextSwapId(
    SwapCompletedCallback completion_callback,
    PresentationCallback presentation_callback) {
  uint64_t swap_id = swap_id_++;
  pending_swap_callbacks_.emplace(swap_id, std::move(completion_callback));
  if (!presentation_callback.is_null()) {
    pending_presentation_callbacks_.emplace(swap_id,
                                            std::move(presentation_callback));
  }
  return swap_id;
}

void GLES2Implementation::TexImage2D(
    GLenum target, GLint level, GLint internalformat, GLsizei width,
    GLsizei height, GLint border, GLenum format, GLenum type,
    const void* pixels) {
  const char* func_name = "glTexImage2D";
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glTexImage2D("
      << GLES2Util::GetStringTextureTarget(target) << ", "
      << level << ", "
      << GLES2Util::GetStringTextureInternalFormat(internalformat) << ", "
      << width << ", " << height << ", " << border << ", "
      << GLES2Util::GetStringTextureFormat(format) << ", "
      << GLES2Util::GetStringPixelType(type) << ", "
      << static_cast<const void*>(pixels) << ")");
  if (level < 0 || height < 0 || width < 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "dimension < 0");
    return;
  }
  if (border != 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "border != 0");
    return;
  }
  if ((bound_pixel_unpack_buffer_ || pixels) &&
      (unpack_skip_pixels_ + width >
       (unpack_row_length_ ? unpack_row_length_ : width))) {
    // This is WebGL 2 specific constraints, but we do it for all ES3 contexts.
    SetGLError(GL_INVALID_OPERATION, func_name,
               "invalid unpack params combination");
    return;
  }

  uint32_t size;
  uint32_t unpadded_row_size;
  uint32_t padded_row_size;
  uint32_t skip_size;
  PixelStoreParams params = GetUnpackParameters(k2D);

  if (!GLES2Util::ComputeImageDataSizesES3(width, height, 1,
                                           format, type,
                                           params,
                                           &size,
                                           &unpadded_row_size,
                                           &padded_row_size,
                                           &skip_size,
                                           nullptr)) {
    SetGLError(GL_INVALID_VALUE, func_name, "image size too large");
    return;
  }

  if (bound_pixel_unpack_buffer_) {
    base::CheckedNumeric<uint32_t> offset = ToGLuint(pixels);
    offset += skip_size;
    if (!offset.IsValid()) {
      SetGLError(GL_INVALID_VALUE, func_name, "skip size too large");
      return;
    }
    helper_->TexImage2D(
        target, level, internalformat, width, height, format, type,
        0, offset.ValueOrDefault(0));
    CheckGLError();
    return;
  }

  // If there's a pixel unpack buffer bound use it when issuing TexImage2D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    if (unpack_row_length_ > 0 || unpack_image_height_ > 0 ||
        unpack_skip_pixels_ > 0 || unpack_skip_rows_ > 0 ||
        unpack_skip_images_ > 0) {
      SetGLError(GL_INVALID_OPERATION, func_name,
                 "No ES3 pack parameters with pixel unpack transfer buffer.");
      return;
    }
    DCHECK_EQ(0u, skip_size);
    GLuint offset = ToGLuint(pixels);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_, func_name, offset, size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->TexImage2D(
          target, level, internalformat, width, height, format, type,
          buffer->shm_id(), buffer->shm_offset() + offset);
      buffer->set_last_usage_token(helper_->InsertToken());
      CheckGLError();
    }
    return;
  }

  // If there's no data just issue TexImage2D
  if (!pixels || width == 0 || height == 0) {
    helper_->TexImage2D(
       target, level, internalformat, width, height, format, type, 0, 0);
    CheckGLError();
    return;
  }

  // Compute the advance bytes per row on the service side.
  // Note |size| is recomputed here if needed.
  uint32_t service_padded_row_size;
  if (unpack_row_length_ > 0 && unpack_row_length_ != width) {
    // All parameters have been applied to the data that are sent to the
    // service side except UNPACK_ALIGNMENT.
    PixelStoreParams service_params;
    service_params.alignment = unpack_alignment_;
    if (!GLES2Util::ComputeImageDataSizesES3(width, height, 1,
                                             format, type,
                                             service_params,
                                             &size,
                                             nullptr,
                                             &service_padded_row_size,
                                             nullptr,
                                             nullptr)) {
      SetGLError(GL_INVALID_VALUE, func_name, "image size too large");
      return;
    }
  } else {
    service_padded_row_size = padded_row_size;
  }

  // advance pixels pointer past the skip rows and skip pixels
  pixels = reinterpret_cast<const int8_t*>(pixels) + skip_size;

  // Check if we can send it all at once.
  int32_t shm_id = 0;
  uint32_t shm_offset = 0;
  void* buffer_pointer = nullptr;

  ScopedTransferBufferPtr transfer_alloc(size, helper_, transfer_buffer_);
  ScopedMappedMemoryPtr mapped_alloc(0, helper_, mapped_memory_.get());

  if (transfer_alloc.valid() && transfer_alloc.size() >= size) {
    shm_id = transfer_alloc.shm_id();
    shm_offset = transfer_alloc.offset();
    buffer_pointer = transfer_alloc.address();
  } else if (size < max_extra_transfer_buffer_size_) {
    mapped_alloc.Reset(size);
    if (mapped_alloc.valid()) {
      transfer_alloc.Discard();

      mapped_alloc.SetFlushAfterRelease(true);
      shm_id = mapped_alloc.shm_id();
      shm_offset = mapped_alloc.offset();
      buffer_pointer = mapped_alloc.address();
    }
  }

  if (buffer_pointer) {
    CopyRectToBuffer(
        pixels, height, unpadded_row_size, padded_row_size,
        buffer_pointer, service_padded_row_size);
    helper_->TexImage2D(
        target, level, internalformat, width, height, format, type,
        shm_id, shm_offset);
    CheckGLError();
    return;
  }

  // No, so send it using TexSubImage2D.
  helper_->TexImage2D(
     target, level, internalformat, width, height, format, type,
     0, 0);
  TexSubImage2DImpl(
      target, level, 0, 0, width, height, format, type, unpadded_row_size,
      pixels, padded_row_size, GL_TRUE, &transfer_alloc,
      service_padded_row_size);
  CheckGLError();
}

void GLES2Implementation::TexImage3D(
    GLenum target, GLint level, GLint internalformat, GLsizei width,
    GLsizei height, GLsizei depth, GLint border, GLenum format, GLenum type,
    const void* pixels) {
  const char* func_name = "glTexImage3D";
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glTexImage3D("
      << GLES2Util::GetStringTextureTarget(target) << ", "
      << level << ", "
      << GLES2Util::GetStringTextureInternalFormat(internalformat) << ", "
      << width << ", " << height << ", " << depth << ", " << border << ", "
      << GLES2Util::GetStringTextureFormat(format) << ", "
      << GLES2Util::GetStringPixelType(type) << ", "
      << static_cast<const void*>(pixels) << ")");
  if (level < 0 || height < 0 || width < 0 || depth < 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "dimension < 0");
    return;
  }
  if (border != 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "border != 0");
    return;
  }
  if ((bound_pixel_unpack_buffer_ || pixels) &&
      ((unpack_skip_pixels_ + width >
        (unpack_row_length_ ? unpack_row_length_ : width)) ||
       (unpack_skip_rows_ + height >
        (unpack_image_height_ ? unpack_image_height_ : height)))) {
    // This is WebGL 2 specific constraints, but we do it for all ES3 contexts.
    SetGLError(GL_INVALID_OPERATION, func_name,
               "invalid unpack params combination");
    return;
  }

  uint32_t size;
  uint32_t unpadded_row_size;
  uint32_t padded_row_size;
  uint32_t skip_size;
  PixelStoreParams params = GetUnpackParameters(k3D);
  if (!GLES2Util::ComputeImageDataSizesES3(width, height, depth,
                                           format, type,
                                           params,
                                           &size,
                                           &unpadded_row_size,
                                           &padded_row_size,
                                           &skip_size,
                                           nullptr)) {
    SetGLError(GL_INVALID_VALUE, func_name, "image size too large");
    return;
  }

  if (bound_pixel_unpack_buffer_) {
    base::CheckedNumeric<uint32_t> offset = ToGLuint(pixels);
    offset += skip_size;
    if (!offset.IsValid()) {
      SetGLError(GL_INVALID_VALUE, func_name, "skip size too large");
      return;
    }
    helper_->TexImage3D(
        target, level, internalformat, width, height, depth, format, type,
        0, offset.ValueOrDefault(0));
    CheckGLError();
    return;
  }

  // If there's a pixel unpack buffer bound use it when issuing TexImage3D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    if (unpack_row_length_ > 0 || unpack_image_height_ > 0 ||
        unpack_skip_pixels_ > 0 || unpack_skip_rows_ > 0 ||
        unpack_skip_images_ > 0) {
      SetGLError(GL_INVALID_OPERATION, func_name,
                 "No ES3 pack parameters with pixel unpack transfer buffer.");
      return;
    }
    DCHECK_EQ(0u, skip_size);
    GLuint offset = ToGLuint(pixels);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_, func_name, offset, size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->TexImage3D(
          target, level, internalformat, width, height, depth, format, type,
          buffer->shm_id(), buffer->shm_offset() + offset);
      buffer->set_last_usage_token(helper_->InsertToken());
      CheckGLError();
    }
    return;
  }

  // If there's no data just issue TexImage3D
  if (!pixels || width == 0 || height == 0 || depth == 0) {
    helper_->TexImage3D(
       target, level, internalformat, width, height, depth, format, type,
       0, 0);
    CheckGLError();
    return;
  }

  // Compute the advance bytes per row on the service side.
  // Note |size| is recomputed here if needed.
  uint32_t service_padded_row_size;
  if ((unpack_row_length_ > 0 && unpack_row_length_ != width) ||
      (unpack_image_height_ > 0 && unpack_image_height_ != height)) {
    // All parameters have been applied to the data that are sent to the
    // service side except UNPACK_ALIGNMENT.
    PixelStoreParams service_params;
    service_params.alignment = unpack_alignment_;
    if (!GLES2Util::ComputeImageDataSizesES3(width, height, depth,
                                             format, type,
                                             service_params,
                                             &size,
                                             nullptr,
                                             &service_padded_row_size,
                                             nullptr,
                                             nullptr)) {
      SetGLError(GL_INVALID_VALUE, func_name, "image size too large");
      return;
    }
  } else {
    service_padded_row_size = padded_row_size;
  }
  uint32_t src_height =
      unpack_image_height_ > 0 ? unpack_image_height_ : height;

  // advance pixels pointer past the skip images/rows/pixels
  pixels = reinterpret_cast<const int8_t*>(pixels) + skip_size;

  // Check if we can send it all at once.
  int32_t shm_id = 0;
  uint32_t shm_offset = 0;
  void* buffer_pointer = nullptr;

  ScopedTransferBufferPtr transfer_alloc(size, helper_, transfer_buffer_);
  ScopedMappedMemoryPtr mapped_alloc(0, helper_, mapped_memory_.get());

  if (transfer_alloc.valid() && transfer_alloc.size() >= size) {
    shm_id = transfer_alloc.shm_id();
    shm_offset = transfer_alloc.offset();
    buffer_pointer = transfer_alloc.address();
  } else if (size < max_extra_transfer_buffer_size_) {
    mapped_alloc.Reset(size);
    if (mapped_alloc.valid()) {
      transfer_alloc.Discard();

      mapped_alloc.SetFlushAfterRelease(true);
      shm_id = mapped_alloc.shm_id();
      shm_offset = mapped_alloc.offset();
      buffer_pointer = mapped_alloc.address();
    }
  }

  if (buffer_pointer) {
    for (GLsizei z = 0; z < depth; ++z) {
      CopyRectToBuffer(
          pixels, height, unpadded_row_size, padded_row_size,
          buffer_pointer, service_padded_row_size);
      pixels = reinterpret_cast<const int8_t*>(pixels) +
               padded_row_size * src_height;
      buffer_pointer = reinterpret_cast<int8_t*>(buffer_pointer) +
                       service_padded_row_size * height;
    }
    helper_->TexImage3D(
        target, level, internalformat, width, height, depth, format, type,
        shm_id, shm_offset);
    CheckGLError();
    return;
  }

  // No, so send it using TexSubImage3D.
  helper_->TexImage3D(
     target, level, internalformat, width, height, depth, format, type,
     0, 0);
  TexSubImage3DImpl(
      target, level, 0, 0, 0, width, height, depth, format, type,
      unpadded_row_size, pixels, padded_row_size, GL_TRUE, &transfer_alloc,
      service_padded_row_size);
  CheckGLError();
}

void GLES2Implementation::TexSubImage2D(
    GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width,
    GLsizei height, GLenum format, GLenum type, const void* pixels) {
  const char* func_name = "glTexSubImage2D";
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glTexSubImage2D("
      << GLES2Util::GetStringTextureTarget(target) << ", "
      << level << ", "
      << xoffset << ", " << yoffset << ", "
      << width << ", " << height << ", "
      << GLES2Util::GetStringTextureFormat(format) << ", "
      << GLES2Util::GetStringPixelType(type) << ", "
      << static_cast<const void*>(pixels) << ")");

  if (level < 0 || height < 0 || width < 0 || xoffset < 0 || yoffset < 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "dimension < 0");
    return;
  }
  if (unpack_skip_pixels_ + width >
      (unpack_row_length_ ? unpack_row_length_ : width)) {
    // This is WebGL 2 specific constraints, but we do it for all ES3 contexts.
    SetGLError(GL_INVALID_OPERATION, func_name,
               "invalid unpack params combination");
    return;
  }

  uint32_t size;
  uint32_t unpadded_row_size;
  uint32_t padded_row_size;
  uint32_t skip_size;
  PixelStoreParams params = GetUnpackParameters(k2D);
  if (!GLES2Util::ComputeImageDataSizesES3(width, height, 1,
                                           format, type,
                                           params,
                                           &size,
                                           &unpadded_row_size,
                                           &padded_row_size,
                                           &skip_size,
                                           nullptr)) {
    SetGLError(GL_INVALID_VALUE, func_name, "image size to large");
    return;
  }

  if (bound_pixel_unpack_buffer_) {
    base::CheckedNumeric<uint32_t> offset = ToGLuint(pixels);
    offset += skip_size;
    if (!offset.IsValid()) {
      SetGLError(GL_INVALID_VALUE, func_name, "skip size too large");
      return;
    }
    helper_->TexSubImage2D(target, level, xoffset, yoffset, width, height,
                           format, type, 0, offset.ValueOrDefault(0), false);
    CheckGLError();
    return;
  }

  // If there's a pixel unpack buffer bound use it when issuing TexSubImage2D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    if (unpack_row_length_ > 0 || unpack_image_height_ > 0 ||
        unpack_skip_pixels_ > 0 || unpack_skip_rows_ > 0 ||
        unpack_skip_images_ > 0) {
      SetGLError(GL_INVALID_OPERATION, func_name,
                 "No ES3 pack parameters with pixel unpack transfer buffer.");
      return;
    }
    DCHECK_EQ(0u, skip_size);
    GLuint offset = ToGLuint(pixels);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_, func_name, offset, size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->TexSubImage2D(
          target, level, xoffset, yoffset, width, height, format, type,
          buffer->shm_id(), buffer->shm_offset() + offset, false);
      buffer->set_last_usage_token(helper_->InsertToken());
      CheckGLError();
    }
    return;
  }

  if (width == 0 || height == 0) {
    // No need to worry about pixel data.
    helper_->TexSubImage2D(target, level, xoffset, yoffset, width, height,
                           format, type, 0, 0, false);
    CheckGLError();
    return;
  }

  // Compute the advance bytes per row on the service side.
  // Note |size| is recomputed here if needed.
  uint32_t service_padded_row_size;
  if (unpack_row_length_ > 0 && unpack_row_length_ != width) {
    // All parameters have been applied to the data that are sent to the
    // service side except UNPACK_ALIGNMENT.
    PixelStoreParams service_params;
    service_params.alignment = unpack_alignment_;
    if (!GLES2Util::ComputeImageDataSizesES3(width, height, 1,
                                             format, type,
                                             service_params,
                                             &size,
                                             nullptr,
                                             &service_padded_row_size,
                                             nullptr,
                                             nullptr)) {
      SetGLError(GL_INVALID_VALUE, func_name, "image size too large");
      return;
    }
  } else {
    service_padded_row_size = padded_row_size;
  }

  // advance pixels pointer past the skip rows and skip pixels
  pixels = reinterpret_cast<const int8_t*>(pixels) + skip_size;

  ScopedTransferBufferPtr buffer(size, helper_, transfer_buffer_);
  base::CheckedNumeric<GLint> checked_xoffset = xoffset;
  checked_xoffset += width;
  if (!checked_xoffset.IsValid()) {
    SetGLError(GL_INVALID_VALUE, "TexSubImage2D", "xoffset + width overflows");
    return;
  }
  base::CheckedNumeric<GLint> checked_yoffset = yoffset;
  checked_yoffset += height;
  if (!checked_yoffset.IsValid()) {
    SetGLError(GL_INVALID_VALUE, "TexSubImage2D", "yoffset + height overflows");
    return;
  }
  TexSubImage2DImpl(
      target, level, xoffset, yoffset, width, height, format, type,
      unpadded_row_size, pixels, padded_row_size, GL_FALSE, &buffer,
      service_padded_row_size);
  CheckGLError();
}

void GLES2Implementation::TexSubImage3D(
    GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint zoffset,
    GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLenum type,
    const void* pixels) {
  const char* func_name = "glTexSubImage3D";
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glTexSubImage3D("
      << GLES2Util::GetStringTextureTarget(target) << ", "
      << level << ", "
      << xoffset << ", " << yoffset << ", " << zoffset << ", "
      << width << ", " << height << ", " << depth << ", "
      << GLES2Util::GetStringTextureFormat(format) << ", "
      << GLES2Util::GetStringPixelType(type) << ", "
      << static_cast<const void*>(pixels) << ")");

  if (level < 0 || height < 0 || width < 0 || depth < 0 ||
      xoffset < 0 || yoffset < 0 || zoffset < 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "dimension < 0");
    return;
  }
  if ((unpack_skip_pixels_ + width >
       (unpack_row_length_ ? unpack_row_length_ : width)) ||
      (unpack_skip_rows_ + height >
       (unpack_image_height_ ? unpack_image_height_ : height))) {
    // This is WebGL 2 specific constraints, but we do it for all ES3 contexts.
    SetGLError(GL_INVALID_OPERATION, func_name,
               "invalid unpack params combination");
    return;
  }

  uint32_t size;
  uint32_t unpadded_row_size;
  uint32_t padded_row_size;
  uint32_t skip_size;
  PixelStoreParams params = GetUnpackParameters(k3D);
  if (!GLES2Util::ComputeImageDataSizesES3(width, height, depth,
                                           format, type,
                                           params,
                                           &size,
                                           &unpadded_row_size,
                                           &padded_row_size,
                                           &skip_size,
                                           nullptr)) {
    SetGLError(GL_INVALID_VALUE, func_name, "image size to large");
    return;
  }

  if (bound_pixel_unpack_buffer_) {
    base::CheckedNumeric<uint32_t> offset = ToGLuint(pixels);
    offset += skip_size;
    if (!offset.IsValid()) {
      SetGLError(GL_INVALID_VALUE, func_name, "skip size too large");
      return;
    }
    helper_->TexSubImage3D(
        target, level, xoffset, yoffset, zoffset, width, height, depth,
        format, type, 0, offset.ValueOrDefault(0), false);
    CheckGLError();
    return;
  }

  // If there's a pixel unpack buffer bound use it when issuing TexSubImage2D.
  if (bound_pixel_unpack_transfer_buffer_id_) {
    if (unpack_row_length_ > 0 || unpack_image_height_ > 0 ||
        unpack_skip_pixels_ > 0 || unpack_skip_rows_ > 0 ||
        unpack_skip_images_ > 0) {
      SetGLError(GL_INVALID_OPERATION, func_name,
                 "No ES3 pack parameters with pixel unpack transfer buffer.");
      return;
    }
    DCHECK_EQ(0u, skip_size);
    GLuint offset = ToGLuint(pixels);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_unpack_transfer_buffer_id_, func_name, offset, size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->TexSubImage3D(
          target, level, xoffset, yoffset, zoffset, width, height, depth,
          format, type, buffer->shm_id(), buffer->shm_offset() + offset, false);
      buffer->set_last_usage_token(helper_->InsertToken());
      CheckGLError();
    }
    return;
  }

  if (width == 0 || height == 0 || depth == 0) {
    // No need to worry about pixel data.
    helper_->TexSubImage3D(target, level, xoffset, yoffset, zoffset,
                           width, height, depth, format, type, 0, 0, false);
    CheckGLError();
    return;
  }

  // Compute the advance bytes per row on the service side
  // Note |size| is recomputed here if needed.
  uint32_t service_padded_row_size;
  if ((unpack_row_length_ > 0 && unpack_row_length_ != width) ||
      (unpack_image_height_ > 0 && unpack_image_height_ != height)) {
    PixelStoreParams service_params;
    service_params.alignment = unpack_alignment_;
    if (!GLES2Util::ComputeImageDataSizesES3(width, height, depth,
                                             format, type,
                                             service_params,
                                             &size,
                                             nullptr,
                                             &service_padded_row_size,
                                             nullptr,
                                             nullptr)) {
      SetGLError(GL_INVALID_VALUE, func_name, "image size too large");
      return;
    }
  } else {
    service_padded_row_size = padded_row_size;
  }

  // advance pixels pointer past the skip images/rows/pixels
  pixels = reinterpret_cast<const int8_t*>(pixels) + skip_size;

  ScopedTransferBufferPtr buffer(size, helper_, transfer_buffer_);
  base::CheckedNumeric<GLint> checked_xoffset = xoffset;
  checked_xoffset += width;
  if (!checked_xoffset.IsValid()) {
    SetGLError(GL_INVALID_VALUE, "TexSubImage3D", "xoffset + width overflows");
    return;
  }
  base::CheckedNumeric<GLint> checked_yoffset = yoffset;
  checked_yoffset += height;
  if (!checked_yoffset.IsValid()) {
    SetGLError(GL_INVALID_VALUE, "TexSubImage3D", "yoffset + height overflows");
    return;
  }
  base::CheckedNumeric<GLint> checked_zoffset = zoffset;
  checked_zoffset += depth;
  if (!checked_zoffset.IsValid()) {
    SetGLError(GL_INVALID_VALUE, "TexSubImage3D", "zoffset + depth overflows");
    return;
  }
  TexSubImage3DImpl(
      target, level, xoffset, yoffset, zoffset, width, height, depth,
      format, type, unpadded_row_size, pixels, padded_row_size, GL_FALSE,
      &buffer, service_padded_row_size);
  CheckGLError();
}

static GLint ComputeNumRowsThatFitInBuffer(uint32_t padded_row_size,
                                           uint32_t unpadded_row_size,
                                           unsigned int size,
                                           GLsizei remaining_rows) {
  DCHECK_GE(unpadded_row_size, 0u);
  if (padded_row_size == 0) {
    return 1;
  }
  GLint num_rows = size / padded_row_size;
  if (num_rows + 1 == remaining_rows &&
      size - num_rows * padded_row_size >= unpadded_row_size) {
    num_rows++;
  }
  return num_rows;
}

void GLES2Implementation::TexSubImage2DImpl(GLenum target,
                                            GLint level,
                                            GLint xoffset,
                                            GLint yoffset,
                                            GLsizei width,
                                            GLsizei height,
                                            GLenum format,
                                            GLenum type,
                                            uint32_t unpadded_row_size,
                                            const void* pixels,
                                            uint32_t pixels_padded_row_size,
                                            GLboolean internal,
                                            ScopedTransferBufferPtr* buffer,
                                            uint32_t buffer_padded_row_size) {
  DCHECK(buffer);
  DCHECK_GE(level, 0);
  DCHECK_GT(height, 0);
  DCHECK_GT(width, 0);
  DCHECK_GE(xoffset, 0);
  DCHECK_GE(yoffset, 0);

  const int8_t* source = reinterpret_cast<const int8_t*>(pixels);
  // Transfer by rows.
  while (height) {
    unsigned int desired_size =
        buffer_padded_row_size * (height - 1) + unpadded_row_size;
    if (!buffer->valid() || buffer->size() == 0) {
      buffer->Reset(desired_size);
      if (!buffer->valid()) {
        return;
      }
    }

    GLint num_rows = ComputeNumRowsThatFitInBuffer(
        buffer_padded_row_size, unpadded_row_size, buffer->size(), height);
    num_rows = std::min(num_rows, height);
    CopyRectToBuffer(
        source, num_rows, unpadded_row_size, pixels_padded_row_size,
        buffer->address(), buffer_padded_row_size);
    helper_->TexSubImage2D(
        target, level, xoffset, yoffset, width, num_rows, format, type,
        buffer->shm_id(), buffer->offset(), internal);
    buffer->Release();
    yoffset += num_rows;
    source += num_rows * pixels_padded_row_size;
    height -= num_rows;
  }
}

void GLES2Implementation::TexSubImage3DImpl(GLenum target,
                                            GLint level,
                                            GLint xoffset,
                                            GLint yoffset,
                                            GLsizei zoffset,
                                            GLsizei width,
                                            GLsizei height,
                                            GLsizei depth,
                                            GLenum format,
                                            GLenum type,
                                            uint32_t unpadded_row_size,
                                            const void* pixels,
                                            uint32_t pixels_padded_row_size,
                                            GLboolean internal,
                                            ScopedTransferBufferPtr* buffer,
                                            uint32_t buffer_padded_row_size) {
  DCHECK(buffer);
  DCHECK_GE(level, 0);
  DCHECK_GT(width, 0);
  DCHECK_GT(height, 0);
  DCHECK_GT(depth, 0);
  DCHECK_GE(xoffset, 0);
  DCHECK_GE(yoffset, 0);
  DCHECK_GE(zoffset, 0);
  const int8_t* source = reinterpret_cast<const int8_t*>(pixels);
  GLsizei total_rows = height * depth;
  GLint row_index = 0, depth_index = 0;
  while (total_rows) {
    // Each time, we either copy one or more images, or copy one or more rows
    // within a single image, depending on the buffer size limit.
    GLsizei max_rows;
    unsigned int desired_size;
    if (row_index > 0) {
      // We are in the middle of an image. Send the remaining of the image.
      max_rows = height - row_index;
      if (total_rows <= height) {
        // Last image, so last row is unpadded.
        desired_size = buffer_padded_row_size * (max_rows - 1) +
            unpadded_row_size;
      } else {
        desired_size = buffer_padded_row_size * max_rows;
      }
    } else {
      // Send all the remaining data if possible.
      max_rows = total_rows;
      desired_size =
          buffer_padded_row_size * (max_rows - 1) + unpadded_row_size;
    }
    if (!buffer->valid() || buffer->size() == 0) {
      buffer->Reset(desired_size);
      if (!buffer->valid()) {
        return;
      }
    }
    GLint num_rows = ComputeNumRowsThatFitInBuffer(
        buffer_padded_row_size, unpadded_row_size, buffer->size(), total_rows);
    num_rows = std::min(num_rows, max_rows);
    GLint num_images = num_rows / height;
    GLsizei my_height, my_depth;
    if (num_images > 0) {
      num_rows = num_images * height;
      my_height = height;
      my_depth = num_images;
    } else {
      my_height = num_rows;
      my_depth = 1;
    }

    if (num_images > 0) {
      int8_t* buffer_pointer = reinterpret_cast<int8_t*>(buffer->address());
      uint32_t src_height =
          unpack_image_height_ > 0 ? unpack_image_height_ : height;
      uint32_t image_size_dst = buffer_padded_row_size * height;
      uint32_t image_size_src = pixels_padded_row_size * src_height;
      for (GLint ii = 0; ii < num_images; ++ii) {
        CopyRectToBuffer(
            source + ii * image_size_src, my_height, unpadded_row_size,
            pixels_padded_row_size, buffer_pointer + ii * image_size_dst,
            buffer_padded_row_size);
      }
    } else {
      CopyRectToBuffer(
          source, my_height, unpadded_row_size, pixels_padded_row_size,
          buffer->address(), buffer_padded_row_size);
    }
    helper_->TexSubImage3D(
        target, level, xoffset, yoffset + row_index, zoffset + depth_index,
        width, my_height, my_depth,
        format, type, buffer->shm_id(), buffer->offset(), internal);
    buffer->Release();

    total_rows -= num_rows;
    if (total_rows > 0) {
      GLint num_image_paddings;
      if (num_images > 0) {
        DCHECK_EQ(row_index, 0);
        depth_index += num_images;
        num_image_paddings = num_images;
      } else {
        row_index = (row_index + my_height) % height;
        num_image_paddings = 0;
        if (my_height > 0 && row_index == 0) {
          depth_index++;
          num_image_paddings++;
        }
      }
      source += num_rows * pixels_padded_row_size;
      if (unpack_image_height_ > height && num_image_paddings > 0) {
        source += num_image_paddings * (unpack_image_height_ - height) *
            pixels_padded_row_size;
      }
    }
  }
}

bool GLES2Implementation::GetActiveAttribHelper(
    GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
    GLenum* type, char* name) {
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  typedef cmds::GetActiveAttrib::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  // Set as failed so if the command fails we'll recover.
  result->success = false;
  helper_->GetActiveAttrib(program, index, kResultBucketId,
                           GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  if (result->success) {
    if (size) {
      *size = result->size;
    }
    if (type) {
      *type = result->type;
    }
    if (length || name) {
      std::vector<int8_t> str;
      GetBucketContents(kResultBucketId, &str);
      GLsizei max_size = std::min(static_cast<size_t>(bufsize) - 1,
                                  std::max(static_cast<size_t>(0),
                                           str.size() - 1));
      if (length) {
        *length = max_size;
      }
      if (name && bufsize > 0) {
        memcpy(name, &str[0], max_size);
        name[max_size] = '\0';
      }
    }
  }
  return result->success != 0;
}

void GLES2Implementation::GetActiveAttrib(
    GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
    GLenum* type, char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetActiveAttrib("
      << program << ", " << index << ", " << bufsize << ", "
      << static_cast<const void*>(length) << ", "
      << static_cast<const void*>(size) << ", "
      << static_cast<const void*>(type) << ", "
      << static_cast<const void*>(name) << ", ");
  if (bufsize < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetActiveAttrib", "bufsize < 0");
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetActiveAttrib");
  bool success = share_group_->program_info_manager()->GetActiveAttrib(
        this, program, index, bufsize, length, size, type, name);
  if (success) {
    if (size) {
      GPU_CLIENT_LOG("  size: " << *size);
    }
    if (type) {
      GPU_CLIENT_LOG("  type: " << GLES2Util::GetStringEnum(*type));
    }
    if (name) {
      GPU_CLIENT_LOG("  name: " << name);
    }
  }
  CheckGLError();
}

bool GLES2Implementation::GetActiveUniformHelper(
    GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
    GLenum* type, char* name) {
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  typedef cmds::GetActiveUniform::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  // Set as failed so if the command fails we'll recover.
  result->success = false;
  helper_->GetActiveUniform(program, index, kResultBucketId,
                            GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  if (result->success) {
    if (size) {
      *size = result->size;
    }
    if (type) {
      *type = result->type;
    }
    if (length || name) {
      std::vector<int8_t> str;
      GetBucketContents(kResultBucketId, &str);
      GLsizei max_size = std::min(static_cast<size_t>(bufsize) - 1,
                                  std::max(static_cast<size_t>(0),
                                           str.size() - 1));
      if (length) {
        *length = max_size;
      }
      if (name && bufsize > 0) {
        memcpy(name, &str[0], max_size);
        name[max_size] = '\0';
      }
    }
  }
  return result->success != 0;
}

void GLES2Implementation::GetActiveUniform(
    GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
    GLenum* type, char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetActiveUniform("
      << program << ", " << index << ", " << bufsize << ", "
      << static_cast<const void*>(length) << ", "
      << static_cast<const void*>(size) << ", "
      << static_cast<const void*>(type) << ", "
      << static_cast<const void*>(name) << ", ");
  if (bufsize < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetActiveUniform", "bufsize < 0");
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetActiveUniform");
  bool success = share_group_->program_info_manager()->GetActiveUniform(
      this, program, index, bufsize, length, size, type, name);
  if (success) {
    if (size) {
      GPU_CLIENT_LOG("  size: " << *size);
    }
    if (type) {
      GPU_CLIENT_LOG("  type: " << GLES2Util::GetStringEnum(*type));
    }
    if (name) {
      GPU_CLIENT_LOG("  name: " << name);
    }
  }
  CheckGLError();
}

bool GLES2Implementation::GetActiveUniformBlockNameHelper(
    GLuint program, GLuint index, GLsizei bufsize,
    GLsizei* length, char* name) {
  DCHECK_LE(0, bufsize);
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  typedef cmds::GetActiveUniformBlockName::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  // Set as failed so if the command fails we'll recover.
  *result = 0;
  helper_->GetActiveUniformBlockName(program, index, kResultBucketId,
                                     GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  if (*result) {
    if (bufsize == 0) {
      if (length) {
        *length = 0;
      }
    } else if (length || name) {
      std::vector<int8_t> str;
      GetBucketContents(kResultBucketId, &str);
      DCHECK_GT(str.size(), 0u);
      GLsizei max_size =
          std::min(bufsize, static_cast<GLsizei>(str.size())) - 1;
      if (length) {
        *length = max_size;
      }
      if (name) {
        memcpy(name, &str[0], max_size);
        name[max_size] = '\0';
      }
    }
  }
  return *result != 0;
}

void GLES2Implementation::GetActiveUniformBlockName(
    GLuint program, GLuint index, GLsizei bufsize,
    GLsizei* length, char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetActiveUniformBlockName("
      << program << ", " << index << ", " << bufsize << ", "
      << static_cast<const void*>(length) << ", "
      << static_cast<const void*>(name) << ")");
  if (bufsize < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetActiveUniformBlockName", "bufsize < 0");
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetActiveUniformBlockName");
  bool success =
      share_group_->program_info_manager()->GetActiveUniformBlockName(
          this, program, index, bufsize, length, name);
  if (success) {
    if (name) {
      GPU_CLIENT_LOG("  name: " << name);
    }
  }
  CheckGLError();
}

bool GLES2Implementation::GetActiveUniformBlockivHelper(
    GLuint program, GLuint index, GLenum pname, GLint* params) {
  typedef cmds::GetActiveUniformBlockiv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  result->SetNumResults(0);
  helper_->GetActiveUniformBlockiv(
      program, index, pname, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  if (result->GetNumResults() > 0) {
    if (params) {
      result->CopyResult(params);
    }
    GPU_CLIENT_LOG_CODE_BLOCK({
      for (int32_t i = 0; i < result->GetNumResults(); ++i) {
        GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
      }
    });
    return true;
  }
  return false;
}

void GLES2Implementation::GetActiveUniformBlockiv(
    GLuint program, GLuint index, GLenum pname, GLint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetActiveUniformBlockiv("
      << program << ", " << index << ", "
      << GLES2Util::GetStringUniformBlockParameter(pname) << ", "
      << static_cast<const void*>(params) << ")");
  TRACE_EVENT0("gpu", "GLES2::GetActiveUniformBlockiv");
  bool success =
      share_group_->program_info_manager()->GetActiveUniformBlockiv(
          this, program, index, pname, params);
  if (success) {
    if (params) {
      // TODO(zmo): For GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, there will
      // be more than one value returned in params.
      GPU_CLIENT_LOG("  params: " << params[0]);
    }
  }
  CheckGLError();
}

bool GLES2Implementation::GetActiveUniformsivHelper(
    GLuint program, GLsizei count, const GLuint* indices,
    GLenum pname, GLint* params) {
  typedef cmds::GetActiveUniformsiv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  result->SetNumResults(0);
  base::CheckedNumeric<size_t> bytes = static_cast<size_t>(count);
  bytes *= sizeof(GLuint);
  if (!bytes.IsValid()) {
    SetGLError(GL_INVALID_VALUE, "glGetActiveUniformsiv", "count overflow");
    return false;
  }
  SetBucketContents(kResultBucketId, indices, bytes.ValueOrDefault(0));
  helper_->GetActiveUniformsiv(
      program, kResultBucketId, pname, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  bool success = result->GetNumResults() == count;
  if (success) {
    if (params) {
      result->CopyResult(params);
    }
    GPU_CLIENT_LOG_CODE_BLOCK({
      for (int32_t i = 0; i < result->GetNumResults(); ++i) {
        GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
      }
    });
  }
  helper_->SetBucketSize(kResultBucketId, 0);
  return success;
}

void GLES2Implementation::GetActiveUniformsiv(
    GLuint program, GLsizei count, const GLuint* indices,
    GLenum pname, GLint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetActiveUniformsiv("
      << program << ", " << count << ", "
      << static_cast<const void*>(indices) << ", "
      << GLES2Util::GetStringUniformParameter(pname) << ", "
      << static_cast<const void*>(params) << ")");
  TRACE_EVENT0("gpu", "GLES2::GetActiveUniformsiv");
  if (count < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetActiveUniformsiv", "count < 0");
    return;
  }
  bool success = share_group_->program_info_manager()->GetActiveUniformsiv(
      this, program, count, indices, pname, params);
  if (success) {
    if (params) {
      GPU_CLIENT_LOG_CODE_BLOCK({
        for (GLsizei ii = 0; ii < count; ++ii) {
          GPU_CLIENT_LOG("  " << ii << ": " << params[ii]);
        }
      });
    }
  }
  CheckGLError();
}

void GLES2Implementation::GetAttachedShaders(
    GLuint program, GLsizei maxcount, GLsizei* count, GLuint* shaders) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetAttachedShaders("
      << program << ", " << maxcount << ", "
      << static_cast<const void*>(count) << ", "
      << static_cast<const void*>(shaders) << ", ");
  if (maxcount < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetAttachedShaders", "maxcount < 0");
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetAttachedShaders");
  typedef cmds::GetAttachedShaders::Result Result;
  uint32_t size = Result::ComputeSize(maxcount);
  Result* result = static_cast<Result*>(transfer_buffer_->Alloc(size));
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetAttachedShaders(
    program,
    transfer_buffer_->GetShmId(),
    transfer_buffer_->GetOffset(result),
    size);
  int32_t token = helper_->InsertToken();
  WaitForCmd();
  if (count) {
    *count = result->GetNumResults();
  }
  result->CopyResult(shaders);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  transfer_buffer_->FreePendingToken(result, token);
  CheckGLError();
}

void GLES2Implementation::GetShaderPrecisionFormat(
    GLenum shadertype, GLenum precisiontype, GLint* range, GLint* precision) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetShaderPrecisionFormat("
      << GLES2Util::GetStringShaderType(shadertype) << ", "
      << GLES2Util::GetStringShaderPrecision(precisiontype) << ", "
      << static_cast<const void*>(range) << ", "
      << static_cast<const void*>(precision) << ", ");
  TRACE_EVENT0("gpu", "GLES2::GetShaderPrecisionFormat");
  typedef cmds::GetShaderPrecisionFormat::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }

  GLStaticState::ShaderPrecisionKey key(shadertype, precisiontype);
  GLStaticState::ShaderPrecisionMap::iterator i =
      static_state_.shader_precisions.find(key);
  if (i != static_state_.shader_precisions.end()) {
    *result = i->second;
  } else {
    result->success = false;
    helper_->GetShaderPrecisionFormat(
        shadertype, precisiontype, GetResultShmId(), GetResultShmOffset());
    WaitForCmd();
    if (result->success)
      static_state_.shader_precisions[key] = *result;
  }

  if (result->success) {
    if (range) {
      range[0] = result->min_range;
      range[1] = result->max_range;
      GPU_CLIENT_LOG("  min_range: " << range[0]);
      GPU_CLIENT_LOG("  min_range: " << range[1]);
    }
    if (precision) {
      precision[0] = result->precision;
      GPU_CLIENT_LOG("  min_range: " << precision[0]);
    }
  }
  CheckGLError();
}

const GLubyte* GLES2Implementation::GetStringHelper(GLenum name) {
  if (name == GL_EXTENSIONS && cached_extension_string_) {
    return reinterpret_cast<const GLubyte*>(cached_extension_string_);
  }
  const char* result = NULL;
  // Clears the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  helper_->GetString(name, kResultBucketId);
  std::string str;
  if (GetBucketAsString(kResultBucketId, &str)) {
    // Adds extensions implemented on client side only.
    if (name == GL_EXTENSIONS) {
      str += std::string(str.empty() ? "" : " ") +
             "GL_CHROMIUM_image "
             "GL_CHROMIUM_map_sub "
             "GL_CHROMIUM_ordering_barrier "
             "GL_CHROMIUM_sync_point "
             "GL_EXT_unpack_subimage";
    }

    // Because of WebGL the extensions can change. We have to cache each unique
    // result since we don't know when the client will stop referring to a
    // previous one it queries.
    // TODO: Here we could save memory by defining RequestExtensions
    // invalidating the GL_EXTENSIONS string. http://crbug.com/586414
    const std::string& cache = *gl_strings_.insert(str).first;
    result = cache.c_str();

    if (name == GL_EXTENSIONS) {
      cached_extension_string_ = result;
      std::vector<std::string> extensions =
          base::SplitString(cache, base::kWhitespaceASCII,
                            base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
      for (const std::string& extension : extensions) {
        cached_extensions_.push_back(
            gl_strings_.insert(extension).first->c_str());
      }
    }
  }
  return reinterpret_cast<const GLubyte*>(result);
}

const GLubyte* GLES2Implementation::GetString(GLenum name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetString("
      << GLES2Util::GetStringStringType(name) << ")");
  TRACE_EVENT0("gpu", "GLES2::GetString");
  const GLubyte* result = GetStringHelper(name);
  GPU_CLIENT_LOG("  returned " << reinterpret_cast<const char*>(result));
  CheckGLError();
  return result;
}

const GLubyte* GLES2Implementation::GetStringi(GLenum name, GLuint index) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetStringi("
                     << GLES2Util::GetStringStringType(name) << "," << index
                     << ")");
  TRACE_EVENT0("gpu", "GLES2::GetStringi");
  UpdateCachedExtensionsIfNeeded();
  if (name != GL_EXTENSIONS) {
    SetGLError(GL_INVALID_ENUM, "glGetStringi", "name");
    return nullptr;
  }
  if (index >= cached_extensions_.size()) {
    SetGLError(GL_INVALID_VALUE, "glGetStringi", "index too large");
    return nullptr;
  }

  const char* result = cached_extensions_[index];
  GPU_CLIENT_LOG("  returned " << result);
  CheckGLError();
  return reinterpret_cast<const GLubyte*>(result);
}

bool GLES2Implementation::GetTransformFeedbackVaryingHelper(
    GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
    GLenum* type, char* name) {
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  typedef cmds::GetTransformFeedbackVarying::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  // Set as failed so if the command fails we'll recover.
  result->success = false;
  helper_->GetTransformFeedbackVarying(
      program, index, kResultBucketId, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  if (result->success) {
    if (size) {
      *size = result->size;
    }
    if (type) {
      *type = result->type;
    }
    if (length || name) {
      std::vector<int8_t> str;
      GetBucketContents(kResultBucketId, &str);
      GLsizei max_size = std::min(bufsize, static_cast<GLsizei>(str.size()));
      if (max_size > 0) {
        --max_size;
      }
      if (length) {
        *length = max_size;
      }
      if (name) {
        if (max_size > 0) {
          memcpy(name, &str[0], max_size);
          name[max_size] = '\0';
        } else if (bufsize > 0) {
          name[0] = '\0';
        }
      }
    }
  }
  return result->success != 0;
}

void GLES2Implementation::GetTransformFeedbackVarying(
    GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
    GLenum* type, char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetTransformFeedbackVarying("
      << program << ", " << index << ", " << bufsize << ", "
      << static_cast<const void*>(length) << ", "
      << static_cast<const void*>(size) << ", "
      << static_cast<const void*>(type) << ", "
      << static_cast<const void*>(name) << ", ");
  if (bufsize < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetTransformFeedbackVarying",
               "bufsize < 0");
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetTransformFeedbackVarying");
  bool success =
      share_group_->program_info_manager()->GetTransformFeedbackVarying(
          this, program, index, bufsize, length, size, type, name);
  if (success) {
    if (size) {
      GPU_CLIENT_LOG("  size: " << *size);
    }
    if (type) {
      GPU_CLIENT_LOG("  type: " << GLES2Util::GetStringEnum(*type));
    }
    if (name) {
      GPU_CLIENT_LOG("  name: " << name);
    }
  }
  CheckGLError();
}

void GLES2Implementation::GetUniformfv(
    GLuint program, GLint location, GLfloat* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetUniformfv("
      << program << ", " << location << ", "
      << static_cast<const void*>(params) << ")");
  TRACE_EVENT0("gpu", "GLES2::GetUniformfv");
  typedef cmds::GetUniformfv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetUniformfv(
      program, location, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  result->CopyResult(params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  CheckGLError();
}

void GLES2Implementation::GetUniformiv(
    GLuint program, GLint location, GLint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetUniformiv("
      << program << ", " << location << ", "
      << static_cast<const void*>(params) << ")");
  TRACE_EVENT0("gpu", "GLES2::GetUniformiv");
  typedef cmds::GetUniformiv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetUniformiv(
      program, location, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  GetResultAs<cmds::GetUniformiv::Result*>()->CopyResult(params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  CheckGLError();
}

void GLES2Implementation::GetUniformuiv(
    GLuint program, GLint location, GLuint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetUniformuiv("
      << program << ", " << location << ", "
      << static_cast<const void*>(params) << ")");
  TRACE_EVENT0("gpu", "GLES2::GetUniformuiv");
  typedef cmds::GetUniformuiv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetUniformuiv(
      program, location, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  GetResultAs<cmds::GetUniformuiv::Result*>()->CopyResult(params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  CheckGLError();
}

void GLES2Implementation::ReadPixels(
    GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format,
    GLenum type, void* pixels) {
  const char* func_name = "glReadPixels";
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glReadPixels("
      << xoffset << ", " << yoffset << ", "
      << width << ", " << height << ", "
      << GLES2Util::GetStringReadPixelFormat(format) << ", "
      << GLES2Util::GetStringPixelType(type) << ", "
      << static_cast<const void*>(pixels) << ")");
  if (width < 0 || height < 0) {
    SetGLError(GL_INVALID_VALUE, func_name, "dimensions < 0");
    return;
  }

  if (pack_skip_pixels_ + width >
      (pack_row_length_ ? pack_row_length_ : width)) {
    // This is WebGL 2 specific constraints, but we do it for all ES3 contexts.
    SetGLError(GL_INVALID_OPERATION, func_name,
               "invalid pack params combination");
    return;
  }

  // glReadPixel pads the size of each row of pixels by an amount specified by
  // glPixelStorei. So, we have to take that into account both in the fact that
  // the pixels returned from the ReadPixel command will include that padding
  // and that when we copy the results to the user's buffer we need to not
  // write those padding bytes but leave them as they are.

  TRACE_EVENT0("gpu", "GLES2::ReadPixels");
  typedef cmds::ReadPixels::Result Result;

  uint32_t size;
  uint32_t unpadded_row_size;
  uint32_t padded_row_size;
  uint32_t skip_size;
  PixelStoreParams params;
  params.alignment = pack_alignment_;
  params.row_length = pack_row_length_;
  params.skip_pixels = pack_skip_pixels_;
  params.skip_rows = pack_skip_rows_;
  if (!GLES2Util::ComputeImageDataSizesES3(width, height, 1,
                                           format, type,
                                           params,
                                           &size,
                                           &unpadded_row_size,
                                           &padded_row_size,
                                           &skip_size,
                                           nullptr)) {
    SetGLError(GL_INVALID_VALUE, func_name, "size too large.");
    return;
  }

  if (bound_pixel_pack_buffer_) {
    base::CheckedNumeric<GLuint> offset = ToGLuint(pixels);
    offset += skip_size;
    if (!offset.IsValid()) {
      SetGLError(GL_INVALID_VALUE, func_name, "skip size too large.");
      return;
    }
    helper_->ReadPixels(xoffset, yoffset, width, height, format, type, 0,
                        offset.ValueOrDefault(0), 0, 0, false);
    InvalidateReadbackBufferShadowDataCHROMIUM(bound_pixel_pack_buffer_);

    CheckGLError();
    return;
  }

  uint32_t service_padded_row_size = 0;
  if (pack_row_length_ > 0 && pack_row_length_ != width) {
    if (!GLES2Util::ComputeImagePaddedRowSize(width,
                                              format, type,
                                              pack_alignment_,
                                              &service_padded_row_size)) {
      SetGLError(GL_INVALID_VALUE, func_name, "size too large.");
      return;
    }
  } else {
    service_padded_row_size = padded_row_size;
  }

  if (bound_pixel_pack_transfer_buffer_id_) {
    if (pack_row_length_ > 0 || pack_skip_pixels_ > 0 || pack_skip_rows_ > 0) {
      SetGLError(GL_INVALID_OPERATION, func_name,
                 "No ES3 pack parameters with pixel pack transfer buffer.");
      return;
    }
    DCHECK_EQ(0u, skip_size);
    GLuint offset = ToGLuint(pixels);
    BufferTracker::Buffer* buffer = GetBoundPixelTransferBufferIfValid(
        bound_pixel_pack_transfer_buffer_id_, func_name, offset, size);
    if (buffer && buffer->shm_id() != -1) {
      helper_->ReadPixels(xoffset, yoffset, width, height, format, type,
                          buffer->shm_id(), buffer->shm_offset() + offset,
                          0, 0, true);
      CheckGLError();
    }
    return;
  }

  if (!pixels) {
    SetGLError(GL_INVALID_OPERATION, func_name, "pixels = NULL");
    return;
  }

  int8_t* dest = reinterpret_cast<int8_t*>(pixels);
  // Advance pixels pointer past the skip rows and skip pixels
  dest += skip_size;

  // Transfer by rows.
  // The max rows we can transfer.
  GLsizei remaining_rows = height;
  GLint y_index = yoffset;
  uint32_t group_size = GLES2Util::ComputeImageGroupSize(format, type);
  uint32_t skip_row_bytes = 0;
  if (xoffset < 0) {
    skip_row_bytes = static_cast<uint32_t>(-xoffset) * group_size;
  }
  do {
    // Even if height == 0, we still need to trigger the service side handling
    // in case invalid args are passed in and a GL errro needs to be generated.
    GLsizei desired_size = remaining_rows == 0 ? 0 :
        service_padded_row_size * (remaining_rows - 1) + unpadded_row_size;
    ScopedTransferBufferPtr buffer(desired_size, helper_, transfer_buffer_);
    if (!buffer.valid()) {
      break;
    }
    GLint num_rows = ComputeNumRowsThatFitInBuffer(
        service_padded_row_size, unpadded_row_size, buffer.size(),
        remaining_rows);
    // NOTE: We must look up the address of the result area AFTER allocation
    // of the transfer buffer since the transfer buffer may be reallocated.
    Result* result = GetResultAs<Result*>();
    if (!result) {
      break;
    }
    result->success = 0;  // mark as failed.
    result->row_length = 0;
    result->num_rows = 0;
    helper_->ReadPixels(
        xoffset, y_index, width, num_rows, format, type,
        buffer.shm_id(), buffer.offset(),
        GetResultShmId(), GetResultShmOffset(),
        false);
    WaitForCmd();
    // If it was not marked as successful exit.
    if (!result->success) {
      break;
    }
    if (remaining_rows == 0) {
      break;
    }
    const uint8_t* src = static_cast<const uint8_t*>(buffer.address());
    if (padded_row_size == unpadded_row_size &&
        (pack_row_length_ == 0 || pack_row_length_ == width) &&
        result->row_length == width && result->num_rows == num_rows) {
      // The pixels are tightly packed.
      uint32_t copy_size = unpadded_row_size * num_rows;
      memcpy(dest, src, copy_size);
      dest += copy_size;
    } else if (result->row_length > 0 && result->num_rows > 0) {
      uint32_t copy_row_size = result->row_length * group_size;
      uint32_t copy_last_row_size = copy_row_size;
      if (copy_row_size + skip_row_bytes > padded_row_size) {
        // We need to avoid writing into next row in case the leading pixels
        // are out-of-bounds and they need to be left untouched.
        copy_row_size = padded_row_size - skip_row_bytes;
      }
      // We have to copy 1 row at a time to avoid writing padding bytes.
      GLint copied_rows = 0;
      for (GLint yy = 0; yy < num_rows; ++yy) {
        if (y_index + yy >= 0 && copied_rows < result->num_rows) {
          if (yy + 1 == num_rows && remaining_rows == num_rows) {
            memcpy(dest + skip_row_bytes, src + skip_row_bytes,
                   copy_last_row_size);
          } else {
            memcpy(dest + skip_row_bytes, src + skip_row_bytes, copy_row_size);
          }
          ++copied_rows;
        }
        dest += padded_row_size;
        src += service_padded_row_size;
      }
      DCHECK_EQ(result->num_rows, copied_rows);
    }
    y_index += num_rows;
    remaining_rows -= num_rows;
  } while (remaining_rows);
  CheckGLError();
}

void GLES2Implementation::ActiveTexture(GLenum texture) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glActiveTexture("
      << GLES2Util::GetStringEnum(texture) << ")");
  GLuint texture_index = texture - GL_TEXTURE0;
  if (texture_index >=
      static_cast<GLuint>(capabilities_.max_combined_texture_image_units)) {
    SetGLErrorInvalidEnum(
        "glActiveTexture", texture, "texture");
    return;
  }

  active_texture_unit_ = texture_index;
  helper_->ActiveTexture(texture);
  CheckGLError();
}

void GLES2Implementation::GenBuffersHelper(
    GLsizei /* n */, const GLuint* /* buffers */) {
}

void GLES2Implementation::GenFramebuffersHelper(
    GLsizei /* n */, const GLuint* /* framebuffers */) {
}

void GLES2Implementation::GenRenderbuffersHelper(
    GLsizei /* n */, const GLuint* /* renderbuffers */) {
}

void GLES2Implementation::GenTexturesHelper(
    GLsizei /* n */, const GLuint* /* textures */) {
}

void GLES2Implementation::GenVertexArraysOESHelper(
    GLsizei n, const GLuint* arrays) {
  vertex_array_object_manager_->GenVertexArrays(n, arrays);
}

void GLES2Implementation::GenQueriesEXTHelper(
    GLsizei /* n */, const GLuint* /* queries */) {
}

void GLES2Implementation::GenSamplersHelper(
    GLsizei /* n */, const GLuint* /* samplers */) {
}

void GLES2Implementation::GenTransformFeedbacksHelper(
    GLsizei /* n */, const GLuint* /* transformfeedbacks */) {
}

// NOTE #1: On old versions of OpenGL, calling glBindXXX with an unused id
// generates a new resource. On newer versions of OpenGL they don't. The code
// related to binding below will need to change if we switch to the new OpenGL
// model. Specifically it assumes a bind will succeed which is always true in
// the old model but possibly not true in the new model if another context has
// deleted the resource.

// NOTE #2: There is a bug in some BindXXXHelpers, that IDs might be marked as
// used even when Bind has failed. However, the bug is minor compared to the
// overhead & duplicated checking in client side.

void GLES2Implementation::BindBufferHelper(
    GLenum target, GLuint buffer_id) {
  // TODO(gman): See note #1 above.
  bool changed = false;
  switch (target) {
    case GL_ARRAY_BUFFER:
      if (bound_array_buffer_ != buffer_id) {
        bound_array_buffer_ = buffer_id;
        changed = true;
      }
      break;
    case GL_COPY_READ_BUFFER:
      if (bound_copy_read_buffer_ != buffer_id) {
        bound_copy_read_buffer_ = buffer_id;
        changed = true;
      }
      break;
    case GL_COPY_WRITE_BUFFER:
      if (bound_copy_write_buffer_ != buffer_id) {
        bound_copy_write_buffer_ = buffer_id;
        changed = true;
      }
      break;
    case GL_ELEMENT_ARRAY_BUFFER:
      changed = vertex_array_object_manager_->BindElementArray(buffer_id);
      break;
    case GL_PIXEL_PACK_BUFFER:
      if (bound_pixel_pack_buffer_ != buffer_id) {
        bound_pixel_pack_buffer_ = buffer_id;
        changed = true;
      }
      break;
    case GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM:
      bound_pixel_pack_transfer_buffer_id_ = buffer_id;
      break;
    case GL_PIXEL_UNPACK_BUFFER:
      if (bound_pixel_unpack_buffer_ != buffer_id) {
        bound_pixel_unpack_buffer_ = buffer_id;
        changed = true;
      }
      break;
    case GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM:
      bound_pixel_unpack_transfer_buffer_id_ = buffer_id;
      break;
    case GL_TRANSFORM_FEEDBACK_BUFFER:
      if (bound_transform_feedback_buffer_ != buffer_id) {
        bound_transform_feedback_buffer_ = buffer_id;
        changed = true;
      }
      break;
    case GL_UNIFORM_BUFFER:
      if (bound_uniform_buffer_ != buffer_id) {
        bound_uniform_buffer_ = buffer_id;
        changed = true;
      }
      break;
    default:
      changed = true;
      break;
  }
  // TODO(gman): See note #2 above.
  if (changed) {
    GetIdHandler(SharedIdNamespaces::kBuffers)
        ->MarkAsUsedForBind(this, target, buffer_id,
                            &GLES2Implementation::BindBufferStub);
  }
}

void GLES2Implementation::BindBufferStub(GLenum target, GLuint buffer) {
  helper_->BindBuffer(target, buffer);
  if (share_group_->bind_generates_resource())
    helper_->CommandBufferHelper::OrderingBarrier();
}

bool GLES2Implementation::UpdateIndexedBufferState(GLenum target,
                                                   GLuint index,
                                                   GLuint buffer_id,
                                                   const char* function_name) {
  switch (target) {
    case GL_TRANSFORM_FEEDBACK_BUFFER:
      if (index >=
          static_cast<GLuint>(
              capabilities_.max_transform_feedback_separate_attribs)) {
        SetGLError(GL_INVALID_VALUE, function_name, "index out of range");
        return false;
      }
      bound_transform_feedback_buffer_ = buffer_id;
      break;
    case GL_UNIFORM_BUFFER:
      if (index >=
          static_cast<GLuint>(capabilities_.max_uniform_buffer_bindings)) {
        SetGLError(GL_INVALID_VALUE, function_name, "index out of range");
        return false;
      }
      bound_uniform_buffer_ = buffer_id;
      break;
    default:
      SetGLError(GL_INVALID_ENUM, function_name, "invalid target");
      return false;
  }
  return true;
}

void GLES2Implementation::BindBufferBaseHelper(GLenum target,
                                               GLuint index,
                                               GLuint buffer_id) {
  // TODO(zmo): See note #1 above.
  // TODO(zmo): See note #2 above.
  if (UpdateIndexedBufferState(target, index, buffer_id, "glBindBufferBase")) {
    GetIdHandler(SharedIdNamespaces::kBuffers)
        ->MarkAsUsedForBind(this, target, index, buffer_id,
                            &GLES2Implementation::BindBufferBaseStub);
  }
}

void GLES2Implementation::BindBufferBaseStub(
    GLenum target, GLuint index, GLuint buffer) {
  helper_->BindBufferBase(target, index, buffer);
  if (share_group_->bind_generates_resource())
    helper_->CommandBufferHelper::Flush();
}

void GLES2Implementation::BindBufferRangeHelper(
    GLenum target, GLuint index, GLuint buffer_id,
    GLintptr offset, GLsizeiptr size) {
  // TODO(zmo): See note #1 above.
  // TODO(zmo): See note #2 above.
  if (UpdateIndexedBufferState(target, index, buffer_id, "glBindBufferRange")) {
    GetIdHandler(SharedIdNamespaces::kBuffers)
        ->MarkAsUsedForBind(this, target, index, buffer_id, offset, size,
                            &GLES2Implementation::BindBufferRangeStub);
  }
}

void GLES2Implementation::BindBufferRangeStub(
    GLenum target, GLuint index, GLuint buffer,
    GLintptr offset, GLsizeiptr size) {
  helper_->BindBufferRange(target, index, buffer, offset, size);
  if (share_group_->bind_generates_resource())
    helper_->CommandBufferHelper::Flush();
}

void GLES2Implementation::BindFramebufferHelper(
    GLenum target, GLuint framebuffer) {
  // TODO(gman): See note #1 above.
  bool changed = false;
  switch (target) {
    case GL_FRAMEBUFFER:
      if (bound_framebuffer_ != framebuffer ||
          bound_read_framebuffer_ != framebuffer) {
        bound_framebuffer_ = framebuffer;
        bound_read_framebuffer_ = framebuffer;
        changed = true;
      }
      break;
    case GL_READ_FRAMEBUFFER:
      DCHECK(capabilities_.major_version >= 3 ||
          IsChromiumFramebufferMultisampleAvailable());
      if (bound_read_framebuffer_ != framebuffer) {
        bound_read_framebuffer_ = framebuffer;
        changed = true;
      }
      break;
    case GL_DRAW_FRAMEBUFFER:
      DCHECK(capabilities_.major_version >= 3 ||
          IsChromiumFramebufferMultisampleAvailable());
      if (bound_framebuffer_ != framebuffer) {
        bound_framebuffer_ = framebuffer;
        changed = true;
      }
      break;
    default:
      SetGLErrorInvalidEnum("glBindFramebuffer", target, "target");
      return;
  }

  if (changed) {
    if (framebuffer != 0)
      GetIdAllocator(IdNamespaces::kFramebuffers)->MarkAsUsed(framebuffer);
    helper_->BindFramebuffer(target, framebuffer);
  }
}

void GLES2Implementation::BindRenderbufferHelper(
    GLenum target, GLuint renderbuffer) {
  // TODO(gman): See note #1 above.
  bool changed = false;
  switch (target) {
    case GL_RENDERBUFFER:
      if (bound_renderbuffer_ != renderbuffer) {
        bound_renderbuffer_ = renderbuffer;
        changed = true;
      }
      break;
    default:
      changed = true;
      break;
  }
  // TODO(zmo): See note #2 above.
  if (changed) {
    GetIdHandler(SharedIdNamespaces::kRenderbuffers)
        ->MarkAsUsedForBind(this, target, renderbuffer,
                            &GLES2Implementation::BindRenderbufferStub);
  }
}

void GLES2Implementation::BindRenderbufferStub(GLenum target,
                                               GLuint renderbuffer) {
  helper_->BindRenderbuffer(target, renderbuffer);
  if (share_group_->bind_generates_resource())
    helper_->CommandBufferHelper::OrderingBarrier();
}

void GLES2Implementation::BindSamplerHelper(GLuint unit,
                                            GLuint sampler) {
  helper_->BindSampler(unit, sampler);
}

void GLES2Implementation::BindTextureHelper(GLenum target, GLuint texture) {
  // TODO(gman): See note #1 above.
  // TODO(gman): Change this to false once we figure out why it's failing
  //     on daisy.
  bool changed = true;
  TextureUnit& unit = texture_units_[active_texture_unit_];
  switch (target) {
    case GL_TEXTURE_2D:
      if (unit.bound_texture_2d != texture) {
        unit.bound_texture_2d = texture;
        changed = true;
      }
      break;
    case GL_TEXTURE_CUBE_MAP:
      if (unit.bound_texture_cube_map != texture) {
        unit.bound_texture_cube_map = texture;
        changed = true;
      }
      break;
    case GL_TEXTURE_EXTERNAL_OES:
      if (unit.bound_texture_external_oes != texture) {
        unit.bound_texture_external_oes = texture;
        changed = true;
      }
      break;
    default:
      changed = true;
      break;
  }
  // TODO(gman): See note #2 above.
  if (changed) {
    GetIdHandler(SharedIdNamespaces::kTextures)
        ->MarkAsUsedForBind(this, target, texture,
                            &GLES2Implementation::BindTextureStub);
  }
}

void GLES2Implementation::BindTextureStub(GLenum target, GLuint texture) {
  helper_->BindTexture(target, texture);
  if (share_group_->bind_generates_resource())
    helper_->CommandBufferHelper::OrderingBarrier();
}

void GLES2Implementation::BindTransformFeedbackHelper(
    GLenum target, GLuint transformfeedback) {
  helper_->BindTransformFeedback(target, transformfeedback);
}

void GLES2Implementation::BindVertexArrayOESHelper(GLuint array) {
  bool changed = false;
  if (vertex_array_object_manager_->BindVertexArray(array, &changed)) {
    if (changed) {
      // Unlike other BindXXXHelpers we don't call MarkAsUsedForBind
      // because unlike other resources VertexArrayObject ids must
      // be generated by GenVertexArrays. A random id to Bind will not
      // generate a new object.
      helper_->BindVertexArrayOES(array);
    }
  } else {
    SetGLError(
        GL_INVALID_OPERATION, "glBindVertexArrayOES",
        "id was not generated with glGenVertexArrayOES");
  }
}

void GLES2Implementation::UseProgramHelper(GLuint program) {
  if (current_program_ != program) {
    current_program_ = program;
    helper_->UseProgram(program);
  }
}

bool GLES2Implementation::IsBufferReservedId(GLuint id) {
  return vertex_array_object_manager_->IsReservedId(id);
}

void GLES2Implementation::DeleteBuffersHelper(
    GLsizei n, const GLuint* buffers) {
  if (!GetIdHandler(SharedIdNamespaces::kBuffers)
           ->FreeIds(this, n, buffers,
                     &GLES2Implementation::DeleteBuffersStub)) {
    SetGLError(
        GL_INVALID_VALUE,
        "glDeleteBuffers", "id not created by this context.");
    return;
  }
  for (GLsizei ii = 0; ii < n; ++ii) {
    if (buffers[ii] == bound_array_buffer_) {
      bound_array_buffer_ = 0;
    }
    if (buffers[ii] == bound_copy_read_buffer_) {
      bound_copy_read_buffer_ = 0;
    }
    if (buffers[ii] == bound_copy_write_buffer_) {
      bound_copy_write_buffer_ = 0;
    }
    if (buffers[ii] == bound_pixel_pack_buffer_) {
      bound_pixel_pack_buffer_ = 0;
    }
    if (buffers[ii] == bound_pixel_unpack_buffer_) {
      bound_pixel_unpack_buffer_ = 0;
    }
    if (buffers[ii] == bound_transform_feedback_buffer_) {
      bound_transform_feedback_buffer_ = 0;
    }
    if (buffers[ii] == bound_uniform_buffer_) {
      bound_uniform_buffer_ = 0;
    }
    vertex_array_object_manager_->UnbindBuffer(buffers[ii]);

    BufferTracker::Buffer* buffer = buffer_tracker_->GetBuffer(buffers[ii]);
    if (buffer)
      RemoveTransferBuffer(buffer);

    readback_buffer_shadow_tracker_->RemoveBuffer(buffers[ii]);

    if (buffers[ii] == bound_pixel_unpack_transfer_buffer_id_) {
      bound_pixel_unpack_transfer_buffer_id_ = 0;
    }

    RemoveMappedBufferRangeById(buffers[ii]);
  }
}

void GLES2Implementation::DeleteBuffersStub(
    GLsizei n, const GLuint* buffers) {
  helper_->DeleteBuffersImmediate(n, buffers);
}


void GLES2Implementation::DeleteFramebuffersHelper(
    GLsizei n, const GLuint* framebuffers) {
  helper_->DeleteFramebuffersImmediate(n, framebuffers);
  IdAllocator* id_allocator = GetIdAllocator(IdNamespaces::kFramebuffers);
  for (GLsizei ii = 0; ii < n; ++ii) {
    id_allocator->FreeID(framebuffers[ii]);
    if (framebuffers[ii] == bound_framebuffer_) {
      bound_framebuffer_ = 0;
    }
    if (framebuffers[ii] == bound_read_framebuffer_) {
      bound_read_framebuffer_ = 0;
    }
  }
}

void GLES2Implementation::DeleteRenderbuffersHelper(
    GLsizei n, const GLuint* renderbuffers) {
  if (!GetIdHandler(SharedIdNamespaces::kRenderbuffers)
           ->FreeIds(this, n, renderbuffers,
                     &GLES2Implementation::DeleteRenderbuffersStub)) {
    SetGLError(
        GL_INVALID_VALUE,
        "glDeleteRenderbuffers", "id not created by this context.");
    return;
  }
  for (GLsizei ii = 0; ii < n; ++ii) {
    if (renderbuffers[ii] == bound_renderbuffer_) {
      bound_renderbuffer_ = 0;
    }
  }
}

void GLES2Implementation::DeleteRenderbuffersStub(
    GLsizei n, const GLuint* renderbuffers) {
  helper_->DeleteRenderbuffersImmediate(n, renderbuffers);
}

void GLES2Implementation::DeleteTexturesHelper(
    GLsizei n, const GLuint* textures) {
  if (!GetIdHandler(SharedIdNamespaces::kTextures)
           ->FreeIds(this, n, textures,
                     &GLES2Implementation::DeleteTexturesStub)) {
    SetGLError(
        GL_INVALID_VALUE,
        "glDeleteTextures", "id not created by this context.");
    return;
  }
  for (GLsizei ii = 0; ii < n; ++ii) {
    share_group_->discardable_texture_manager()->FreeTexture(textures[ii]);
  }
  UnbindTexturesHelper(n, textures);
}

void GLES2Implementation::UnbindTexturesHelper(GLsizei n,
                                               const GLuint* textures) {
  for (GLsizei ii = 0; ii < n; ++ii) {
    for (GLint tt = 0; tt < capabilities_.max_combined_texture_image_units;
         ++tt) {
      TextureUnit& unit = texture_units_[tt];
      if (textures[ii] == unit.bound_texture_2d) {
        unit.bound_texture_2d = 0;
      }
      if (textures[ii] == unit.bound_texture_cube_map) {
        unit.bound_texture_cube_map = 0;
      }
      if (textures[ii] == unit.bound_texture_external_oes) {
        unit.bound_texture_external_oes = 0;
      }
    }
  }
}

void GLES2Implementation::DeleteTexturesStub(GLsizei n,
                                             const GLuint* textures) {
  helper_->DeleteTexturesImmediate(n, textures);
}

void GLES2Implementation::DeleteVertexArraysOESHelper(
    GLsizei n, const GLuint* arrays) {
  vertex_array_object_manager_->DeleteVertexArrays(n, arrays);
  helper_->DeleteVertexArraysOESImmediate(n, arrays);
  IdAllocator* id_allocator = GetIdAllocator(IdNamespaces::kVertexArrays);
  for (GLsizei ii = 0; ii < n; ++ii)
    id_allocator->FreeID(arrays[ii]);
}

void GLES2Implementation::DeleteSamplersStub(
    GLsizei n, const GLuint* samplers) {
  helper_->DeleteSamplersImmediate(n, samplers);
}

void GLES2Implementation::DeleteSamplersHelper(
    GLsizei n, const GLuint* samplers) {
  if (!GetIdHandler(SharedIdNamespaces::kSamplers)
           ->FreeIds(this, n, samplers,
                     &GLES2Implementation::DeleteSamplersStub)) {
    SetGLError(
        GL_INVALID_VALUE,
        "glDeleteSamplers", "id not created by this context.");
    return;
  }
}

void GLES2Implementation::DeleteTransformFeedbacksHelper(
    GLsizei n, const GLuint* transformfeedbacks) {
  helper_->DeleteTransformFeedbacksImmediate(n, transformfeedbacks);
  IdAllocator* id_allocator = GetIdAllocator(IdNamespaces::kTransformFeedbacks);
  for (GLsizei ii = 0; ii < n; ++ii)
    id_allocator->FreeID(transformfeedbacks[ii]);
}

void GLES2Implementation::DisableVertexAttribArray(GLuint index) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG(
      "[" << GetLogPrefix() << "] glDisableVertexAttribArray(" << index << ")");
  vertex_array_object_manager_->SetAttribEnable(index, false);
  helper_->DisableVertexAttribArray(index);
  CheckGLError();
}

void GLES2Implementation::EnableVertexAttribArray(GLuint index) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glEnableVertexAttribArray("
      << index << ")");
  vertex_array_object_manager_->SetAttribEnable(index, true);
  helper_->EnableVertexAttribArray(index);
  CheckGLError();
}

void GLES2Implementation::DrawArrays(GLenum mode, GLint first, GLsizei count) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDrawArrays("
      << GLES2Util::GetStringDrawMode(mode) << ", "
      << first << ", " << count << ")");
  if (count < 0) {
    SetGLError(GL_INVALID_VALUE, "glDrawArrays", "count < 0");
    return;
  }
  bool simulated = false;
  if (vertex_array_object_manager_->SupportsClientSideBuffers()) {
    GLsizei num_elements;
    SafeAddInt32(first, count, &num_elements);
    if (!vertex_array_object_manager_->SetupSimulatedClientSideBuffers(
            "glDrawArrays", this, helper_, num_elements, 0, &simulated)) {
      return;
    }
  }
  helper_->DrawArrays(mode, first, count);
  RestoreArrayBuffer(simulated);
  CheckGLError();
}

void GLES2Implementation::GetVertexAttribfv(
    GLuint index, GLenum pname, GLfloat* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetVertexAttribfv("
      << index << ", "
      << GLES2Util::GetStringVertexAttribute(pname) << ", "
      << static_cast<const void*>(params) << ")");
  uint32_t value = 0;
  if (vertex_array_object_manager_->GetVertexAttrib(index, pname, &value)) {
    *params = static_cast<GLfloat>(value);
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetVertexAttribfv");
  typedef cmds::GetVertexAttribfv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetVertexAttribfv(
      index, pname, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  result->CopyResult(params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  CheckGLError();
}

void GLES2Implementation::GetVertexAttribiv(
    GLuint index, GLenum pname, GLint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetVertexAttribiv("
      << index << ", "
      << GLES2Util::GetStringVertexAttribute(pname) << ", "
      << static_cast<const void*>(params) << ")");
  uint32_t value = 0;
  if (vertex_array_object_manager_->GetVertexAttrib(index, pname, &value)) {
    *params = static_cast<GLint>(value);
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetVertexAttribiv");
  typedef cmds::GetVertexAttribiv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetVertexAttribiv(
      index, pname, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  result->CopyResult(params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  CheckGLError();
}

void GLES2Implementation::GetVertexAttribIiv(
    GLuint index, GLenum pname, GLint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetVertexAttribIiv("
      << index << ", "
      << GLES2Util::GetStringVertexAttribute(pname) << ", "
      << static_cast<const void*>(params) << ")");
  uint32_t value = 0;
  if (vertex_array_object_manager_->GetVertexAttrib(index, pname, &value)) {
    *params = static_cast<GLint>(value);
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetVertexAttribIiv");
  typedef cmds::GetVertexAttribiv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetVertexAttribIiv(
      index, pname, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  result->CopyResult(params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  CheckGLError();
}

void GLES2Implementation::GetVertexAttribIuiv(
    GLuint index, GLenum pname, GLuint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetVertexAttribIuiv("
      << index << ", "
      << GLES2Util::GetStringVertexAttribute(pname) << ", "
      << static_cast<const void*>(params) << ")");
  uint32_t value = 0;
  if (vertex_array_object_manager_->GetVertexAttrib(index, pname, &value)) {
    *params = static_cast<GLuint>(value);
    return;
  }
  TRACE_EVENT0("gpu", "GLES2::GetVertexAttribIuiv");
  typedef cmds::GetVertexAttribiv::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetVertexAttribIuiv(
      index, pname, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  result->CopyResult(params);
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  CheckGLError();
}

GLenum GLES2Implementation::GetGraphicsResetStatusKHR() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetGraphicsResetStatusKHR()");
  // If any context (including ourselves) has seen itself become lost,
  // then it will have told the ShareGroup, so just report its status.
  if (share_group_->IsLost())
    return GL_UNKNOWN_CONTEXT_RESET_KHR;
  return GL_NO_ERROR;
}

void GLES2Implementation::Swap(uint32_t flags,
                               SwapCompletedCallback complete_callback,
                               PresentationCallback presentation_callback) {
  SwapBuffers(PrepareNextSwapId(std::move(complete_callback),
                                std::move(presentation_callback)),
              flags);
}

void GLES2Implementation::SwapWithBounds(
    const std::vector<gfx::Rect>& rects,
    uint32_t flags,
    SwapCompletedCallback swap_completed,
    PresentationCallback presentation_callback) {
  std::vector<int> rects_data(rects.size() * 4);
  for (size_t i = 0; i < rects.size(); ++i) {
    rects_data[i * 4 + 0] = rects[i].x();
    rects_data[i * 4 + 1] = rects[i].y();
    rects_data[i * 4 + 2] = rects[i].width();
    rects_data[i * 4 + 3] = rects[i].height();
  }
  SwapBuffersWithBoundsCHROMIUM(
      PrepareNextSwapId(std::move(swap_completed),
                        std::move(presentation_callback)),
      rects.size(), rects_data.data(), flags);
}

void GLES2Implementation::PartialSwapBuffers(
    const gfx::Rect& sub_buffer,
    uint32_t flags,
    SwapCompletedCallback swap_completed,
    PresentationCallback presentation_callback) {
  PostSubBufferCHROMIUM(PrepareNextSwapId(std::move(swap_completed),
                                          std::move(presentation_callback)),
                        sub_buffer.x(), sub_buffer.y(), sub_buffer.width(),
                        sub_buffer.height(), flags);
}

void GLES2Implementation::CommitOverlayPlanes(
    uint32_t flags,
    SwapCompletedCallback swap_completed,
    PresentationCallback presentation_callback) {
  CommitOverlayPlanesCHROMIUM(
      PrepareNextSwapId(std::move(swap_completed),
                        std::move(presentation_callback)),
      flags);
}

static GLenum GetGLESOverlayTransform(gfx::OverlayTransform plane_transform) {
  switch (plane_transform) {
    case gfx::OVERLAY_TRANSFORM_INVALID:
      break;
    case gfx::OVERLAY_TRANSFORM_NONE:
      return GL_OVERLAY_TRANSFORM_NONE_CHROMIUM;
    case gfx::OVERLAY_TRANSFORM_FLIP_HORIZONTAL:
      return GL_OVERLAY_TRANSFORM_FLIP_HORIZONTAL_CHROMIUM;
    case gfx::OVERLAY_TRANSFORM_FLIP_VERTICAL:
      return GL_OVERLAY_TRANSFORM_FLIP_VERTICAL_CHROMIUM;
    case gfx::OVERLAY_TRANSFORM_ROTATE_90:
      return GL_OVERLAY_TRANSFORM_ROTATE_90_CHROMIUM;
    case gfx::OVERLAY_TRANSFORM_ROTATE_180:
      return GL_OVERLAY_TRANSFORM_ROTATE_180_CHROMIUM;
    case gfx::OVERLAY_TRANSFORM_ROTATE_270:
      return GL_OVERLAY_TRANSFORM_ROTATE_270_CHROMIUM;
  }
  NOTREACHED();
  return GL_OVERLAY_TRANSFORM_NONE_CHROMIUM;
}

void GLES2Implementation::ScheduleOverlayPlane(
    int plane_z_order,
    gfx::OverlayTransform plane_transform,
    unsigned overlay_texture_id,
    const gfx::Rect& display_bounds,
    const gfx::RectF& uv_rect,
    bool enable_blend,
    unsigned gpu_fence_id) {
  ScheduleOverlayPlaneCHROMIUM(
      plane_z_order, GetGLESOverlayTransform(plane_transform),
      overlay_texture_id, display_bounds.x(), display_bounds.y(),
      display_bounds.width(), display_bounds.height(), uv_rect.x(), uv_rect.y(),
      uv_rect.width(), uv_rect.height(), enable_blend, gpu_fence_id);
}

void GLES2Implementation::ScheduleCALayerSharedStateCHROMIUM(
    GLfloat opacity,
    GLboolean is_clipped,
    const GLfloat* clip_rect,
    GLint sorting_context_id,
    const GLfloat* transform) {
  size_t shm_size = 20 * sizeof(GLfloat);
  ScopedTransferBufferPtr buffer(shm_size, helper_, transfer_buffer_);
  if (!buffer.valid() || buffer.size() < shm_size) {
    SetGLError(GL_OUT_OF_MEMORY, "GLES2::ScheduleCALayerSharedStateCHROMIUM",
               "out of memory");
    return;
  }
  GLfloat* mem = static_cast<GLfloat*>(buffer.address());
  memcpy(mem + 0, clip_rect, 4 * sizeof(GLfloat));
  memcpy(mem + 4, transform, 16 * sizeof(GLfloat));
  helper_->ScheduleCALayerSharedStateCHROMIUM(opacity, is_clipped,
                                              sorting_context_id,
                                              buffer.shm_id(), buffer.offset());
}

void GLES2Implementation::ScheduleCALayerCHROMIUM(GLuint contents_texture_id,
                                                  const GLfloat* contents_rect,
                                                  GLuint background_color,
                                                  GLuint edge_aa_mask,
                                                  const GLfloat* bounds_rect,
                                                  GLuint filter) {
  size_t shm_size = 8 * sizeof(GLfloat);
  ScopedTransferBufferPtr buffer(shm_size, helper_, transfer_buffer_);
  if (!buffer.valid() || buffer.size() < shm_size) {
    SetGLError(GL_OUT_OF_MEMORY, "GLES2::ScheduleCALayerCHROMIUM",
               "out of memory");
    return;
  }
  GLfloat* mem = static_cast<GLfloat*>(buffer.address());
  memcpy(mem + 0, contents_rect, 4 * sizeof(GLfloat));
  memcpy(mem + 4, bounds_rect, 4 * sizeof(GLfloat));
  helper_->ScheduleCALayerCHROMIUM(contents_texture_id, background_color,
                                   edge_aa_mask, filter, buffer.shm_id(),
                                   buffer.offset());
}

void GLES2Implementation::ScheduleDCLayerSharedStateCHROMIUM(
    GLfloat opacity,
    GLboolean is_clipped,
    const GLfloat* clip_rect,
    GLint z_order,
    const GLfloat* transform) {
  size_t shm_size = 20 * sizeof(GLfloat);
  ScopedTransferBufferPtr buffer(shm_size, helper_, transfer_buffer_);
  if (!buffer.valid() || buffer.size() < shm_size) {
    SetGLError(GL_OUT_OF_MEMORY, "GLES2::ScheduleDCLayerSharedStateCHROMIUM",
               "out of memory");
    return;
  }
  GLfloat* mem = static_cast<GLfloat*>(buffer.address());
  memcpy(mem + 0, clip_rect, 4 * sizeof(GLfloat));
  memcpy(mem + 4, transform, 16 * sizeof(GLfloat));
  helper_->ScheduleDCLayerSharedStateCHROMIUM(opacity, is_clipped, z_order,
                                              buffer.shm_id(), buffer.offset());
}

void GLES2Implementation::SetColorSpaceMetadataCHROMIUM(
    GLuint texture_id,
    GLColorSpace color_space) {
#if defined(__native_client__)
  // Including gfx::ColorSpace would bring Skia and a lot of other code into
  // NaCl's IRT.
  SetGLError(GL_INVALID_VALUE, "GLES2::SetColorSpaceMetadataCHROMIUM",
             "not supported");
#else
  gfx::ColorSpace* gfx_color_space =
      reinterpret_cast<gfx::ColorSpace*>(color_space);
  base::Pickle color_space_data;
  IPC::ParamTraits<gfx::ColorSpace>::Write(&color_space_data, *gfx_color_space);

  ScopedTransferBufferPtr buffer(color_space_data.size(), helper_,
                                 transfer_buffer_);
  if (!buffer.valid() || buffer.size() < color_space_data.size()) {
    SetGLError(GL_OUT_OF_MEMORY, "GLES2::SetColorSpaceMetadataCHROMIUM",
               "out of memory");
    return;
  }
  memcpy(buffer.address(), color_space_data.data(), color_space_data.size());
  helper_->SetColorSpaceMetadataCHROMIUM(
      texture_id, buffer.shm_id(), buffer.offset(), color_space_data.size());
#endif
}

void GLES2Implementation::ScheduleDCLayerCHROMIUM(
    GLsizei num_textures,
    const GLuint* contents_texture_ids,
    const GLfloat* contents_rect,
    GLuint background_color,
    GLuint edge_aa_mask,
    const GLfloat* bounds_rect,
    GLuint filter,
    bool is_protected_video) {
  const size_t kRectsSize = 8 * sizeof(GLfloat);
  size_t textures_size = num_textures * sizeof(GLuint);
  size_t shm_size = kRectsSize + textures_size;
  ScopedTransferBufferPtr buffer(shm_size, helper_, transfer_buffer_);
  if (!buffer.valid() || buffer.size() < shm_size) {
    SetGLError(GL_OUT_OF_MEMORY, "GLES2::ScheduleDCLayerCHROMIUM",
               "out of memory");
    return;
  }
  GLfloat* mem = static_cast<GLfloat*>(buffer.address());
  memcpy(mem + 0, contents_rect, 4 * sizeof(GLfloat));
  memcpy(mem + 4, bounds_rect, 4 * sizeof(GLfloat));
  memcpy(static_cast<char*>(buffer.address()) + kRectsSize,
         contents_texture_ids, textures_size);
  helper_->ScheduleDCLayerCHROMIUM(num_textures, background_color, edge_aa_mask,
                                   filter, buffer.shm_id(), buffer.offset(),
                                   is_protected_video);
}

void GLES2Implementation::CommitOverlayPlanesCHROMIUM(uint64_t swap_id,
                                                      uint32_t flags) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] CommitOverlayPlanesCHROMIUM()");
  TRACE_EVENT0("gpu", "GLES2::CommitOverlayPlanesCHROMIUM");

  // Same flow control as GLES2Implementation::SwapBuffers (see comments there).
  swap_buffers_tokens_.push(helper_->InsertToken());
  helper_->CommitOverlayPlanesCHROMIUM(swap_id, flags);
  helper_->CommandBufferHelper::Flush();
  if (swap_buffers_tokens_.size() > kMaxSwapBuffers + 1) {
    helper_->WaitForToken(swap_buffers_tokens_.front());
    swap_buffers_tokens_.pop();
  }
}

GLboolean GLES2Implementation::EnableFeatureCHROMIUM(
    const char* feature) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glEnableFeatureCHROMIUM("
                 << feature << ")");
  TRACE_EVENT0("gpu", "GLES2::EnableFeatureCHROMIUM");
  typedef cmds::EnableFeatureCHROMIUM::Result Result;
  SetBucketAsCString(kResultBucketId, feature);
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return false;
  }
  *result = 0;
  helper_->EnableFeatureCHROMIUM(
      kResultBucketId, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  helper_->SetBucketSize(kResultBucketId, 0);
  GPU_CLIENT_LOG("   returned " << GLES2Util::GetStringBool(*result));
  return *result != 0;
}

void* GLES2Implementation::MapBufferSubDataCHROMIUM(
    GLuint target, GLintptr offset, GLsizeiptr size, GLenum access) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glMapBufferSubDataCHROMIUM("
      << target << ", " << offset << ", " << size << ", "
      << GLES2Util::GetStringEnum(access) << ")");
  // NOTE: target is NOT checked because the service will check it
  // and we don't know what targets are valid.
  if (access != GL_WRITE_ONLY) {
    SetGLErrorInvalidEnum(
        "glMapBufferSubDataCHROMIUM", access, "access");
    return NULL;
  }
  if (!ValidateSize("glMapBufferSubDataCHROMIUM", size) ||
      !ValidateOffset("glMapBufferSubDataCHROMIUM", offset)) {
    return NULL;
  }

  int32_t shm_id;
  unsigned int shm_offset;
  void* mem = mapped_memory_->Alloc(size, &shm_id, &shm_offset);
  if (!mem) {
    SetGLError(GL_OUT_OF_MEMORY, "glMapBufferSubDataCHROMIUM", "out of memory");
    return NULL;
  }

  std::pair<MappedBufferMap::iterator, bool> result =
     mapped_buffers_.insert(std::make_pair(
         mem,
         MappedBuffer(
             access, shm_id, mem, shm_offset, target, offset, size)));
  DCHECK(result.second);
  GPU_CLIENT_LOG("  returned " << mem);
  return mem;
}

void GLES2Implementation::UnmapBufferSubDataCHROMIUM(const void* mem) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG(
      "[" << GetLogPrefix() << "] glUnmapBufferSubDataCHROMIUM(" << mem << ")");
  MappedBufferMap::iterator it = mapped_buffers_.find(mem);
  if (it == mapped_buffers_.end()) {
    SetGLError(
        GL_INVALID_VALUE, "UnmapBufferSubDataCHROMIUM", "buffer not mapped");
    return;
  }
  const MappedBuffer& mb = it->second;
  helper_->BufferSubData(
      mb.target, mb.offset, mb.size, mb.shm_id, mb.shm_offset);
  InvalidateReadbackBufferShadowDataCHROMIUM(GetBoundBufferHelper(mb.target));
  mapped_memory_->FreePendingToken(mb.shm_memory, helper_->InsertToken());
  mapped_buffers_.erase(it);
  CheckGLError();
}

GLuint GLES2Implementation::GetBoundBufferHelper(GLenum target) {
  GLenum binding = GLES2Util::MapBufferTargetToBindingEnum(target);
  GLint id = 0;
  bool cached = GetHelper(binding, &id);
  DCHECK(cached);
  return static_cast<GLuint>(id);
}

void GLES2Implementation::RemoveMappedBufferRangeByTarget(GLenum target) {
  GLuint buffer = GetBoundBufferHelper(target);
  RemoveMappedBufferRangeById(buffer);
}

void GLES2Implementation::RemoveMappedBufferRangeById(GLuint buffer) {
  if (buffer > 0) {
    auto iter = mapped_buffer_range_map_.find(buffer);
    if (iter != mapped_buffer_range_map_.end() && iter->second.shm_memory) {
      mapped_memory_->FreePendingToken(
          iter->second.shm_memory, helper_->InsertToken());
      mapped_buffer_range_map_.erase(iter);
    }
  }
}

void GLES2Implementation::ClearMappedBufferRangeMap() {
  for (auto& buffer_range : mapped_buffer_range_map_) {
    if (buffer_range.second.shm_memory) {
      mapped_memory_->FreePendingToken(
          buffer_range.second.shm_memory, helper_->InsertToken());
    }
  }
  mapped_buffer_range_map_.clear();
}

void* GLES2Implementation::MapBufferRange(
    GLenum target, GLintptr offset, GLsizeiptr size, GLbitfield access) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glMapBufferRange("
      << GLES2Util::GetStringEnum(target) << ", " << offset << ", "
      << size << ", " << access << ")");
  if (!ValidateSize("glMapBufferRange", size) ||
      !ValidateOffset("glMapBufferRange", offset)) {
    return nullptr;
  }

  GLuint buffer = GetBoundBufferHelper(target);

  void* mem = nullptr;

  // Early return if we have a valid shadow copy for readback
  if (access == GL_MAP_READ_BIT) {
    // This will return an incorrect result if the client does the following:
    // * Writes into a buffer
    // * Issues query (GL_READBACK_SHADOW_COPIES_UPDATED_CHROMIUM)
    // * Writes into the buffer using transform feedback (but doesn't issue
    //   InvalidateReadbackBufferShadowDataCHROMIUM correctly)
    // * Waits on the query
    // * Reads from the buffer (may return results from before the transfom
    //   feedback operation).
    // Therefore, if (and only if) a client uses the
    // GL_READBACK_SHADOW_COPIES_UPDATED_CHROMIUM query, it must also correctly
    // use InvalidateReadbackBufferShadowDataCHROMIUM. WebGL (at the time of
    // this writing) is expected to be the only client which uses
    // GL_READBACK_SHADOW_COPIES_UPDATED_CHROMIUM.
    if (auto* buffer_object =
            readback_buffer_shadow_tracker_->GetBuffer(buffer)) {
      mem = buffer_object->MapReadbackShm(offset, size);
      if (!mem) {
        // (If there's no valid shadow copy, warn and fall back to usual logic.)
        SendErrorMessage(
            "performance warning: READ-usage buffer was read back without "
            "waiting on a fence. This caused a graphics pipeline stall.",
            0);
      }
    }
  }

  // Usual, round-trip path if we're not doing a shadow-copy readback
  int32_t shm_id = 0;
  unsigned int shm_offset = 0;
  if (!mem) {
    mem = mapped_memory_->Alloc(size, &shm_id, &shm_offset);
    if (!mem) {
      SetGLError(GL_OUT_OF_MEMORY, "glMapBufferRange", "out of memory");
      return nullptr;
    }

    typedef cmds::MapBufferRange::Result Result;
    Result* result = GetResultAs<Result*>();
    *result = 0;
    helper_->MapBufferRange(target, offset, size, access, shm_id, shm_offset,
                            GetResultShmId(), GetResultShmOffset());
    // TODO(zmo): For write only mode with MAP_INVALID_*_BIT, we should
    // consider an early return without WaitForCmd(). crbug.com/465804.
    WaitForCmd();
    if (*result) {
      const GLbitfield kInvalidateBits =
          GL_MAP_INVALIDATE_BUFFER_BIT | GL_MAP_INVALIDATE_RANGE_BIT;
      if ((access & kInvalidateBits) != 0) {
        // We do not read back from the buffer, therefore, we set the client
        // side memory to zero to avoid uninitialized data.
        memset(mem, 0, size);
      }
    } else {
      mapped_memory_->Free(mem);
      mem = nullptr;
    }
  }

  // Track this mapping regardless of which path was taken above.
  if (mem) {
    DCHECK_NE(0u, buffer);
    // glMapBufferRange fails on an already mapped buffer.
    DCHECK(mapped_buffer_range_map_.find(buffer) ==
           mapped_buffer_range_map_.end());
    auto iter = mapped_buffer_range_map_.insert(std::make_pair(
        buffer,
        MappedBuffer(access, shm_id, mem, shm_offset, target, offset, size)));
    DCHECK(iter.second);
  }

  GPU_CLIENT_LOG("  returned " << mem);
  CheckGLError();
  return mem;
}

GLboolean GLES2Implementation::UnmapBuffer(GLenum target) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glUnmapBuffer("
      << GLES2Util::GetStringEnum(target) << ")");
  switch (target) {
    case GL_ARRAY_BUFFER:
    case GL_ELEMENT_ARRAY_BUFFER:
    case GL_COPY_READ_BUFFER:
    case GL_COPY_WRITE_BUFFER:
    case GL_PIXEL_PACK_BUFFER:
    case GL_PIXEL_UNPACK_BUFFER:
    case GL_TRANSFORM_FEEDBACK_BUFFER:
    case GL_UNIFORM_BUFFER:
      break;
    default:
      SetGLError(GL_INVALID_ENUM, "glUnmapBuffer", "invalid target");
      return GL_FALSE;
  }
  GLuint buffer = GetBoundBufferHelper(target);
  if (buffer == 0) {
    SetGLError(GL_INVALID_OPERATION, "glUnmapBuffer", "no buffer bound");
    return GL_FALSE;
  }
  auto iter = mapped_buffer_range_map_.find(buffer);
  if (iter == mapped_buffer_range_map_.end()) {
    SetGLError(GL_INVALID_OPERATION, "glUnmapBuffer", "buffer is unmapped");
    return GL_FALSE;
  }

  bool was_mapped_by_readback_tracker = false;
  if (auto* buffer_object =
          readback_buffer_shadow_tracker_->GetBuffer(buffer)) {
    was_mapped_by_readback_tracker = buffer_object->UnmapReadbackShm();
  }
  if (!was_mapped_by_readback_tracker) {
    helper_->UnmapBuffer(target);
    InvalidateReadbackBufferShadowDataCHROMIUM(GetBoundBufferHelper(target));
  }
  RemoveMappedBufferRangeById(buffer);

  // TODO(zmo): There is a rare situation that data might be corrupted and
  // GL_FALSE should be returned. We lose context on that sitatuon, so we
  // don't have to WaitForCmd().
  GPU_CLIENT_LOG("  returned " << GL_TRUE);
  CheckGLError();
  return GL_TRUE;
}

void* GLES2Implementation::MapTexSubImage2DCHROMIUM(
     GLenum target,
     GLint level,
     GLint xoffset,
     GLint yoffset,
     GLsizei width,
     GLsizei height,
     GLenum format,
     GLenum type,
     GLenum access) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glMapTexSubImage2DCHROMIUM("
      << target << ", " << level << ", "
      << xoffset << ", " << yoffset << ", "
      << width << ", " << height << ", "
      << GLES2Util::GetStringTextureFormat(format) << ", "
      << GLES2Util::GetStringPixelType(type) << ", "
      << GLES2Util::GetStringEnum(access) << ")");
  if (access != GL_WRITE_ONLY) {
    SetGLErrorInvalidEnum(
        "glMapTexSubImage2DCHROMIUM", access, "access");
    return NULL;
  }
  // NOTE: target is NOT checked because the service will check it
  // and we don't know what targets are valid.
  if (level < 0 || xoffset < 0 || yoffset < 0 || width < 0 || height < 0) {
    SetGLError(
        GL_INVALID_VALUE, "glMapTexSubImage2DCHROMIUM", "bad dimensions");
    return NULL;
  }
  uint32_t size;
  if (!GLES2Util::ComputeImageDataSizes(
      width, height, 1, format, type, unpack_alignment_, &size, NULL, NULL)) {
    SetGLError(
        GL_INVALID_VALUE, "glMapTexSubImage2DCHROMIUM", "image size too large");
    return NULL;
  }
  int32_t shm_id;
  unsigned int shm_offset;
  void* mem = mapped_memory_->Alloc(size, &shm_id, &shm_offset);
  if (!mem) {
    SetGLError(GL_OUT_OF_MEMORY, "glMapTexSubImage2DCHROMIUM", "out of memory");
    return NULL;
  }

  std::pair<MappedTextureMap::iterator, bool> result =
     mapped_textures_.insert(std::make_pair(
         mem,
         MappedTexture(
             access, shm_id, mem, shm_offset,
             target, level, xoffset, yoffset, width, height, format, type)));
  DCHECK(result.second);
  GPU_CLIENT_LOG("  returned " << mem);
  return mem;
}

void GLES2Implementation::UnmapTexSubImage2DCHROMIUM(const void* mem) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG(
      "[" << GetLogPrefix() << "] glUnmapTexSubImage2DCHROMIUM(" << mem << ")");
  MappedTextureMap::iterator it = mapped_textures_.find(mem);
  if (it == mapped_textures_.end()) {
    SetGLError(
        GL_INVALID_VALUE, "UnmapTexSubImage2DCHROMIUM", "texture not mapped");
    return;
  }
  const MappedTexture& mt = it->second;
  helper_->TexSubImage2D(
      mt.target, mt.level, mt.xoffset, mt.yoffset, mt.width, mt.height,
      mt.format, mt.type, mt.shm_id, mt.shm_offset, GL_FALSE);
  mapped_memory_->FreePendingToken(mt.shm_memory, helper_->InsertToken());
  mapped_textures_.erase(it);
  CheckGLError();
}

void GLES2Implementation::ResizeCHROMIUM(GLuint width,
                                         GLuint height,
                                         float scale_factor,
                                         GLenum color_space,
                                         GLboolean alpha) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glResizeCHROMIUM(" << width << ", "
                     << height << ", " << scale_factor << ", " << alpha << ")");
  helper_->ResizeCHROMIUM(width, height, scale_factor, color_space, alpha);
  CheckGLError();
}

const GLchar* GLES2Implementation::GetRequestableExtensionsCHROMIUM() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix()
      << "] glGetRequestableExtensionsCHROMIUM()");
  TRACE_EVENT0("gpu",
               "GLES2Implementation::GetRequestableExtensionsCHROMIUM()");
  const char* result = NULL;
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  helper_->GetRequestableExtensionsCHROMIUM(kResultBucketId);
  std::string str;
  if (GetBucketAsString(kResultBucketId, &str)) {
    // The set of requestable extensions shrinks as we enable
    // them. Because we don't know when the client will stop referring
    // to a previous one it queries (see GetString) we need to cache
    // the unique results.
    // TODO: Here we could save memory by defining RequestExtensions
    // invalidating the GL_EXTENSIONS string. http://crbug.com/586414
    result = gl_strings_.insert(str).first->c_str();
  }
  GPU_CLIENT_LOG("  returned " << result);
  return reinterpret_cast<const GLchar*>(result);
}

// TODO(gman): Remove this command. It's here for WebGL but is incompatible
// with VirtualGL contexts.
void GLES2Implementation::RequestExtensionCHROMIUM(const char* extension) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glRequestExtensionCHROMIUM("
                 << extension << ")");
  InvalidateCachedExtensions();
  SetBucketAsCString(kResultBucketId, extension);
  helper_->RequestExtensionCHROMIUM(kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);

  struct ExtensionCheck {
    const char* extension;
    ExtensionStatus* status;
  };
  const ExtensionCheck checks[] = {
    {
      "GL_CHROMIUM_framebuffer_multisample",
       &chromium_framebuffer_multisample_,
    },
  };
  const size_t kNumChecks = sizeof(checks)/sizeof(checks[0]);
  for (size_t ii = 0; ii < kNumChecks; ++ii) {
    const ExtensionCheck& check = checks[ii];
    if (*check.status == kUnavailableExtensionStatus &&
        !strcmp(extension, check.extension)) {
      *check.status = kUnknownExtensionStatus;
    }
  }
}

void GLES2Implementation::GetProgramInfoCHROMIUMHelper(
    GLuint program,
    std::vector<int8_t>* result) {
  DCHECK(result);
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  helper_->GetProgramInfoCHROMIUM(program, kResultBucketId);
  GetBucketContents(kResultBucketId, result);
}

void GLES2Implementation::GetProgramInfoCHROMIUM(
    GLuint program, GLsizei bufsize, GLsizei* size, void* info) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  if (bufsize < 0) {
    SetGLError(
        GL_INVALID_VALUE, "glProgramInfoCHROMIUM", "bufsize less than 0.");
    return;
  }
  if (size == NULL) {
    SetGLError(GL_INVALID_VALUE, "glProgramInfoCHROMIUM", "size is null.");
    return;
  }
  // Make sure they've set size to 0 else the value will be undefined on
  // lost context.
  DCHECK_EQ(0, *size);
  std::vector<int8_t> result;
  GetProgramInfoCHROMIUMHelper(program, &result);
  if (result.empty()) {
    return;
  }
  *size = result.size();
  if (!info) {
    return;
  }
  if (static_cast<size_t>(bufsize) < result.size()) {
    SetGLError(GL_INVALID_OPERATION,
               "glProgramInfoCHROMIUM", "bufsize is too small for result.");
    return;
  }
  memcpy(info, &result[0], result.size());
}

void GLES2Implementation::GetUniformBlocksCHROMIUMHelper(
    GLuint program,
    std::vector<int8_t>* result) {
  DCHECK(result);
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  helper_->GetUniformBlocksCHROMIUM(program, kResultBucketId);
  GetBucketContents(kResultBucketId, result);
}

void GLES2Implementation::GetUniformBlocksCHROMIUM(
    GLuint program, GLsizei bufsize, GLsizei* size, void* info) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  if (bufsize < 0) {
    SetGLError(
        GL_INVALID_VALUE, "glGetUniformBlocksCHROMIUM", "bufsize less than 0.");
    return;
  }
  if (size == NULL) {
    SetGLError(GL_INVALID_VALUE, "glGetUniformBlocksCHROMIUM", "size is null.");
    return;
  }
  // Make sure they've set size to 0 else the value will be undefined on
  // lost context.
  DCHECK_EQ(0, *size);
  std::vector<int8_t> result;
  GetUniformBlocksCHROMIUMHelper(program, &result);
  if (result.empty()) {
    return;
  }
  *size = result.size();
  if (!info) {
    return;
  }
  if (static_cast<size_t>(bufsize) < result.size()) {
    SetGLError(GL_INVALID_OPERATION, "glGetUniformBlocksCHROMIUM",
               "bufsize is too small for result.");
    return;
  }
  memcpy(info, &result[0], result.size());
}

void GLES2Implementation::GetUniformsES3CHROMIUMHelper(
    GLuint program,
    std::vector<int8_t>* result) {
  DCHECK(result);
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  helper_->GetUniformsES3CHROMIUM(program, kResultBucketId);
  GetBucketContents(kResultBucketId, result);
}

void GLES2Implementation::GetUniformsES3CHROMIUM(
    GLuint program, GLsizei bufsize, GLsizei* size, void* info) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  if (bufsize < 0) {
    SetGLError(
        GL_INVALID_VALUE, "glGetUniformsES3CHROMIUM", "bufsize less than 0.");
    return;
  }
  if (size == NULL) {
    SetGLError(GL_INVALID_VALUE, "glGetUniformsES3CHROMIUM", "size is null.");
    return;
  }
  // Make sure they've set size to 0 else the value will be undefined on
  // lost context.
  DCHECK_EQ(0, *size);
  std::vector<int8_t> result;
  GetUniformsES3CHROMIUMHelper(program, &result);
  if (result.empty()) {
    return;
  }
  *size = result.size();
  if (!info) {
    return;
  }
  if (static_cast<size_t>(bufsize) < result.size()) {
    SetGLError(GL_INVALID_OPERATION,
               "glGetUniformsES3CHROMIUM", "bufsize is too small for result.");
    return;
  }
  memcpy(info, &result[0], result.size());
}

void GLES2Implementation::GetTransformFeedbackVaryingsCHROMIUMHelper(
    GLuint program,
    std::vector<int8_t>* result) {
  DCHECK(result);
  // Clear the bucket so if the command fails nothing will be in it.
  helper_->SetBucketSize(kResultBucketId, 0);
  helper_->GetTransformFeedbackVaryingsCHROMIUM(program, kResultBucketId);
  GetBucketContents(kResultBucketId, result);
}

void GLES2Implementation::GetTransformFeedbackVaryingsCHROMIUM(
    GLuint program, GLsizei bufsize, GLsizei* size, void* info) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  if (bufsize < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetTransformFeedbackVaryingsCHROMIUM",
               "bufsize less than 0.");
    return;
  }
  if (size == NULL) {
    SetGLError(GL_INVALID_VALUE, "glGetTransformFeedbackVaryingsCHROMIUM",
               "size is null.");
    return;
  }
  // Make sure they've set size to 0 else the value will be undefined on
  // lost context.
  DCHECK_EQ(0, *size);
  std::vector<int8_t> result;
  GetTransformFeedbackVaryingsCHROMIUMHelper(program, &result);
  if (result.empty()) {
    return;
  }
  *size = result.size();
  if (!info) {
    return;
  }
  if (static_cast<size_t>(bufsize) < result.size()) {
    SetGLError(GL_INVALID_OPERATION, "glGetTransformFeedbackVaryingsCHROMIUM",
               "bufsize is too small for result.");
    return;
  }
  memcpy(info, &result[0], result.size());
}

void GLES2Implementation::PostSubBufferCHROMIUM(uint64_t swap_id,
                                                GLint x,
                                                GLint y,
                                                GLint width,
                                                GLint height,
                                                GLbitfield flags) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] PostSubBufferCHROMIUM("
      << x << ", " << y << ", " << width << ", " << height << ")");
  TRACE_EVENT2("gpu", "GLES2::PostSubBufferCHROMIUM",
               "width", width, "height", height);

  // Same flow control as GLES2Implementation::SwapBuffers (see comments there).
  swap_buffers_tokens_.push(helper_->InsertToken());
  helper_->PostSubBufferCHROMIUM(swap_id, x, y, width, height, flags);
  helper_->CommandBufferHelper::Flush();
  if (swap_buffers_tokens_.size() > kMaxSwapBuffers + 1) {
    helper_->WaitForToken(swap_buffers_tokens_.front());
    swap_buffers_tokens_.pop();
  }
}

void GLES2Implementation::DeleteQueriesEXTHelper(
    GLsizei n, const GLuint* queries) {
  IdAllocator* id_allocator = GetIdAllocator(IdNamespaces::kQueries);
  for (GLsizei ii = 0; ii < n; ++ii) {
    query_tracker_->RemoveQuery(queries[ii]);
    id_allocator->FreeID(queries[ii]);
  }

  helper_->DeleteQueriesEXTImmediate(n, queries);
}

GLboolean GLES2Implementation::IsQueryEXT(GLuint id) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] IsQueryEXT(" << id << ")");

  // TODO(gman): To be spec compliant IDs from other contexts sharing
  // resources need to return true here even though you can't share
  // queries across contexts?
  return query_tracker_->GetQuery(id) != NULL;
}

void GLES2Implementation::BeginQueryEXT(GLenum target, GLuint id) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] BeginQueryEXT("
                     << GLES2Util::GetStringQueryTarget(target) << ", " << id
                     << ")");

  switch (target) {
    case GL_COMMANDS_ISSUED_CHROMIUM:
    case GL_LATENCY_QUERY_CHROMIUM:
    case GL_ASYNC_PIXEL_PACK_COMPLETED_CHROMIUM:
    case GL_GET_ERROR_QUERY_CHROMIUM:
      break;
    case GL_READBACK_SHADOW_COPIES_UPDATED_CHROMIUM:
    case GL_COMMANDS_COMPLETED_CHROMIUM:
      if (!capabilities_.sync_query) {
        SetGLError(GL_INVALID_OPERATION, "glBeginQueryEXT",
                   "not enabled for commands completed queries");
        return;
      }
      break;
    case GL_SAMPLES_PASSED_ARB:
      if (!capabilities_.occlusion_query) {
        SetGLError(GL_INVALID_OPERATION, "glBeginQueryEXT",
                   "not enabled for occlusion queries");
        return;
      }
      break;
    case GL_ANY_SAMPLES_PASSED:
    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
      if (!capabilities_.occlusion_query_boolean) {
        SetGLError(GL_INVALID_OPERATION, "glBeginQueryEXT",
                   "not enabled for boolean occlusion queries");
        return;
      }
      break;
    case GL_TIME_ELAPSED_EXT:
      if (!capabilities_.timer_queries) {
        SetGLError(GL_INVALID_OPERATION, "glBeginQueryEXT",
                   "not enabled for timing queries");
        return;
      }
      break;
    case GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN:
      if (capabilities_.major_version >= 3)
        break;
      FALLTHROUGH;
    default:
      SetGLError(GL_INVALID_ENUM, "glBeginQueryEXT", "unknown query target");
      return;
  }

  // if any outstanding queries INV_OP
  if (query_tracker_->GetCurrentQuery(target)) {
    SetGLError(GL_INVALID_OPERATION, "glBeginQueryEXT",
               "query already in progress");
    return;
  }

  if (id == 0) {
    SetGLError(GL_INVALID_OPERATION, "glBeginQueryEXT", "id is 0");
    return;
  }

  if (!GetIdAllocator(IdNamespaces::kQueries)->InUse(id)) {
    SetGLError(GL_INVALID_OPERATION, "glBeginQueryEXT", "invalid id");
    return;
  }

  // Extra setups some targets might need.
  switch (target) {
    case GL_TIME_ELAPSED_EXT:
      if (!query_tracker_->SetDisjointSync(this)) {
        SetGLError(GL_OUT_OF_MEMORY, "glBeginQueryEXT",
                   "buffer allocation failed");
        return;
      }
      break;
    default:
      break;
  }

  if (query_tracker_->BeginQuery(id, target, this))
    CheckGLError();

  if (target == GL_READBACK_SHADOW_COPIES_UPDATED_CHROMIUM) {
    AllocateShadowCopiesForReadback();
  }
}

void GLES2Implementation::AllocateShadowCopiesForReadback() {
  for (auto buffer : readback_buffer_shadow_tracker_->GetUnfencedBufferList()) {
    if (!buffer) {
      continue;
    }
    int32_t shm_id = 0;
    uint32_t shm_offset = 0;
    bool already_allocated = false;
    uint32_t size = buffer->Alloc(&shm_id, &shm_offset, &already_allocated);
    if (already_allocated) {
      SendErrorMessage(
          "performance warning: READ-usage buffer was written, then "
          "fenced, but written again before being read back. This discarded "
          "the shadow copy that was created to accelerate readback.",
          0);
    }
    helper_->SetReadbackBufferShadowAllocationINTERNAL(buffer->id(), shm_id,
                                                       shm_offset, size);
  }
}

void GLES2Implementation::BufferShadowWrittenCallback(
    const ReadbackBufferShadowTracker::BufferList& buffers,
    uint64_t serial) {
  for (const auto& buffer : buffers) {
    if (buffer) {
      buffer->UpdateSerialTo(serial);
    }
  }
}

void GLES2Implementation::EndQueryEXT(GLenum target) {
  QueryTracker::Query* query = nullptr;
  {
    GPU_CLIENT_SINGLE_THREAD_CHECK();
    GPU_CLIENT_LOG("[" << GetLogPrefix() << "] EndQueryEXT("
                       << GLES2Util::GetStringQueryTarget(target) << ")");
    query = query_tracker_->GetCurrentQuery(target);
    if (!query_tracker_->EndQuery(target, this)) {
      return;
    }
    CheckGLError();
  }  // GPU_CLIENT_SINGLE_THREAD_CHECK ends here

  if (target == GL_READBACK_SHADOW_COPIES_UPDATED_CHROMIUM) {
    DCHECK(capabilities_.chromium_nonblocking_readback);
    DCHECK(query);
    GLuint query_id = query->id();
    auto serial = readback_buffer_shadow_tracker_->buffer_shadow_serial();
    readback_buffer_shadow_tracker_->IncrementSerial();
    auto buffers = readback_buffer_shadow_tracker_->TakeUnfencedBufferList();
    SignalQuery(query_id, base::BindOnce(
                              &GLES2Implementation::BufferShadowWrittenCallback,
                              std::move(buffers), serial));
  }
}

void GLES2Implementation::QueryCounterEXT(GLuint id, GLenum target) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] QueryCounterEXT("
                 << id
                 << ", " << GLES2Util::GetStringQueryTarget(target) << ")");

  switch (target) {
    case GL_TIMESTAMP_EXT:
      if (!capabilities_.timer_queries) {
        SetGLError(
            GL_INVALID_OPERATION, "glQueryCounterEXT",
            "not enabled for timing queries");
        return;
      }
      break;
    default:
      SetGLError(
          GL_INVALID_ENUM, "glQueryCounterEXT", "unknown query target");
      return;
  }

  if (id == 0) {
    SetGLError(GL_INVALID_OPERATION, "glQueryCounterEXT", "id is 0");
    return;
  }

  if (!GetIdAllocator(IdNamespaces::kQueries)->InUse(id)) {
    SetGLError(GL_INVALID_OPERATION, "glQueryCounterEXT", "invalid id");
    return;
  }

  // Extra setups some targets might need.
  switch (target) {
    case GL_TIMESTAMP_EXT:
      if (!query_tracker_->SetDisjointSync(this)) {
        SetGLError(GL_OUT_OF_MEMORY,
                   "glQueryCounterEXT",
                   "buffer allocation failed");
        return;
      }
      break;
    default:
      break;
  }

  if (query_tracker_->QueryCounter(id, target, this))
    CheckGLError();
}

void GLES2Implementation::GetQueryivEXT(
    GLenum target, GLenum pname, GLint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] GetQueryivEXT("
                 << GLES2Util::GetStringQueryTarget(target) << ", "
                 << GLES2Util::GetStringQueryParameter(pname) << ", "
                 << static_cast<const void*>(params) << ")");
  if (pname == GL_QUERY_COUNTER_BITS_EXT) {
    switch (target) {
      case GL_TIMESTAMP_EXT:
        // Overall reliable driver support for timestamps is limited, so we
        // disable the timestamp portion of this extension to encourage use of
        // the better supported time elapsed queries.
        *params = 0;
        break;
      case GL_TIME_ELAPSED_EXT:
        // We convert all queries to CPU time so we support 64 bits.
        *params = 64;
        break;
      default:
        SetGLErrorInvalidEnum("glGetQueryivEXT", target, "target");
        break;
    }
    return;
  } else if (pname != GL_CURRENT_QUERY_EXT) {
    SetGLErrorInvalidEnum("glGetQueryivEXT", pname, "pname");
    return;
  }
  QueryTracker::Query* query = query_tracker_->GetCurrentQuery(target);
  *params = query ? query->id() : 0;
  GPU_CLIENT_LOG("  " << *params);
  CheckGLError();
}

void GLES2Implementation::GetQueryObjectivEXT(
    GLuint id, GLenum pname, GLint* params) {
  GLuint64 result = 0;
  if (GetQueryObjectValueHelper("glGetQueryObjectivEXT", id, pname, &result))
    *params = base::saturated_cast<GLint>(result);
}

void GLES2Implementation::GetQueryObjectuivEXT(
    GLuint id, GLenum pname, GLuint* params) {
  GLuint64 result = 0;
  if (GetQueryObjectValueHelper("glGetQueryObjectuivEXT", id, pname, &result))
    *params = base::saturated_cast<GLuint>(result);
}

void GLES2Implementation::GetQueryObjecti64vEXT(
    GLuint id, GLenum pname, GLint64* params) {
  GLuint64 result = 0;
  if (GetQueryObjectValueHelper("glGetQueryObjectiv64vEXT", id, pname, &result))
    *params = base::saturated_cast<GLint64>(result);
}

void GLES2Implementation::GetQueryObjectui64vEXT(
    GLuint id, GLenum pname, GLuint64* params) {
  GLuint64 result = 0;
  if (GetQueryObjectValueHelper("glGetQueryObjectui64vEXT", id, pname, &result))
    *params = result;
}

void GLES2Implementation::SetDisjointValueSyncCHROMIUM() {
  query_tracker_->SetDisjointSync(this);
}

void GLES2Implementation::DrawArraysInstancedANGLE(
    GLenum mode, GLint first, GLsizei count, GLsizei primcount) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDrawArraysInstancedANGLE("
      << GLES2Util::GetStringDrawMode(mode) << ", "
      << first << ", " << count << ", " << primcount << ")");
  if (count < 0) {
    SetGLError(GL_INVALID_VALUE, "glDrawArraysInstancedANGLE", "count < 0");
    return;
  }
  if (primcount < 0) {
    SetGLError(GL_INVALID_VALUE, "glDrawArraysInstancedANGLE", "primcount < 0");
    return;
  }
  if (primcount == 0) {
    return;
  }
  bool simulated = false;
  if (vertex_array_object_manager_->SupportsClientSideBuffers()) {
    GLsizei num_elements;
    SafeAddInt32(first, count, &num_elements);
    if (!vertex_array_object_manager_->SetupSimulatedClientSideBuffers(
            "glDrawArraysInstancedANGLE", this, helper_, num_elements,
            primcount, &simulated)) {
      return;
    }
  }
  helper_->DrawArraysInstancedANGLE(mode, first, count, primcount);
  RestoreArrayBuffer(simulated);
  CheckGLError();
}

void GLES2Implementation::DrawElementsInstancedANGLE(
    GLenum mode, GLsizei count, GLenum type, const void* indices,
    GLsizei primcount) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDrawElementsInstancedANGLE("
      << GLES2Util::GetStringDrawMode(mode) << ", "
      << count << ", "
      << GLES2Util::GetStringIndexType(type) << ", "
      << static_cast<const void*>(indices) << ", "
      << primcount << ")");
  if (count < 0) {
    SetGLError(GL_INVALID_VALUE,
               "glDrawElementsInstancedANGLE", "count less than 0.");
    return;
  }
  if (count == 0) {
    return;
  }
  if (primcount < 0) {
    SetGLError(GL_INVALID_VALUE,
               "glDrawElementsInstancedANGLE", "primcount < 0");
    return;
  }
  if (primcount == 0) {
    return;
  }
  if (vertex_array_object_manager_->bound_element_array_buffer() != 0 &&
      !ValidateOffset("glDrawElementsInstancedANGLE",
                      reinterpret_cast<GLintptr>(indices))) {
    return;
  }
  GLuint offset = 0;
  bool simulated = false;
  if (!vertex_array_object_manager_->SetupSimulatedIndexAndClientSideBuffers(
      "glDrawElementsInstancedANGLE", this, helper_, count, type, primcount,
      indices, &offset, &simulated)) {
    return;
  }
  helper_->DrawElementsInstancedANGLE(mode, count, type, offset, primcount);
  RestoreElementAndArrayBuffers(simulated);
  CheckGLError();
}

void GLES2Implementation::ProduceTextureDirectCHROMIUM(GLuint texture,
                                                       GLbyte* data) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glProduceTextureDirectCHROMIUM("
                     << static_cast<const void*>(data) << ")");
  static_assert(std::is_trivially_copyable<Mailbox>::value,
                "gpu::Mailbox is not trivially copyable");
  Mailbox result = Mailbox::Generate();
  memcpy(data, result.name, sizeof(result.name));
  helper_->ProduceTextureDirectCHROMIUMImmediate(texture, data);
  CheckGLError();
}

GLuint GLES2Implementation::CreateAndConsumeTextureCHROMIUM(
    const GLbyte* data) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCreateAndConsumeTextureCHROMIUM("
                     << static_cast<const void*>(data) << ")");
  const Mailbox& mailbox = *reinterpret_cast<const Mailbox*>(data);
  DCHECK(mailbox.Verify()) << "CreateAndConsumeTextureCHROMIUM was passed a "
                              "mailbox that was not generated by "
                              "ProduceTextureDirectCHROMIUM.";
  GLuint client_id;
  GetIdHandler(SharedIdNamespaces::kTextures)->MakeIds(this, 0, 1, &client_id);
  helper_->CreateAndConsumeTextureINTERNALImmediate(client_id, data);
  if (share_group_->bind_generates_resource())
    helper_->CommandBufferHelper::Flush();
  CheckGLError();
  return client_id;
}

void GLES2Implementation::PushGroupMarkerEXT(
    GLsizei length, const GLchar* marker) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glPushGroupMarkerEXT("
      << length << ", " << marker << ")");
  if (!marker) {
    marker = "";
  }
  SetBucketAsString(
      kResultBucketId,
      (length ? std::string(marker, length) : std::string(marker)));
  helper_->PushGroupMarkerEXT(kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);
  debug_marker_manager_.PushGroup(
      length ? std::string(marker, length) : std::string(marker));
}

void GLES2Implementation::InsertEventMarkerEXT(
    GLsizei length, const GLchar* marker) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glInsertEventMarkerEXT("
      << length << ", " << marker << ")");
  if (!marker) {
    marker = "";
  }
  SetBucketAsString(
      kResultBucketId,
      (length ? std::string(marker, length) : std::string(marker)));
  helper_->InsertEventMarkerEXT(kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);
  debug_marker_manager_.SetMarker(
      length ? std::string(marker, length) : std::string(marker));
}

void GLES2Implementation::PopGroupMarkerEXT() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glPopGroupMarkerEXT()");
  helper_->PopGroupMarkerEXT();
  debug_marker_manager_.PopGroup();
}

void GLES2Implementation::TraceBeginCHROMIUM(
    const char* category_name, const char* trace_name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glTraceBeginCHROMIUM("
                 << category_name << ", " << trace_name << ")");
  SetBucketAsCString(kResultBucketId, category_name);
  SetBucketAsCString(kResultBucketId + 1, trace_name);
  helper_->TraceBeginCHROMIUM(kResultBucketId, kResultBucketId + 1);
  helper_->SetBucketSize(kResultBucketId, 0);
  helper_->SetBucketSize(kResultBucketId + 1, 0);
  current_trace_stack_++;
}

void GLES2Implementation::TraceEndCHROMIUM() {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glTraceEndCHROMIUM(" << ")");
  if (current_trace_stack_ == 0) {
    SetGLError(GL_INVALID_OPERATION, "glTraceEndCHROMIUM",
               "missing begin trace");
    return;
  }
  helper_->TraceEndCHROMIUM();
  current_trace_stack_--;
}

void* GLES2Implementation::MapBufferCHROMIUM(GLuint target, GLenum access) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glMapBufferCHROMIUM("
      << target << ", " << GLES2Util::GetStringEnum(access) << ")");
  switch (target)  {
    case GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM:
      if (access != GL_READ_ONLY) {
        SetGLError(GL_INVALID_ENUM, "glMapBufferCHROMIUM", "bad access mode");
        return NULL;
      }
      break;
    default:
      SetGLError(
          GL_INVALID_ENUM, "glMapBufferCHROMIUM", "invalid target");
      return NULL;
  }
  GLuint buffer_id;
  GetBoundPixelTransferBuffer(target, "glMapBufferCHROMIUM", &buffer_id);
  if (!buffer_id) {
    return NULL;
  }
  BufferTracker::Buffer* buffer = buffer_tracker_->GetBuffer(buffer_id);
  if (!buffer) {
    SetGLError(GL_INVALID_OPERATION, "glMapBufferCHROMIUM", "invalid buffer");
    return NULL;
  }
  if (buffer->mapped()) {
    SetGLError(GL_INVALID_OPERATION, "glMapBufferCHROMIUM", "already mapped");
    return NULL;
  }
  // Here we wait for previous transfer operations to be finished.
  if (buffer->last_usage_token()) {
    helper_->WaitForToken(buffer->last_usage_token());
    buffer->set_last_usage_token(0);
  }
  buffer->set_mapped(true);

  GPU_CLIENT_LOG("  returned " << buffer->address());
  CheckGLError();
  return buffer->address();
}

GLboolean GLES2Implementation::UnmapBufferCHROMIUM(GLuint target) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG(
      "[" << GetLogPrefix() << "] glUnmapBufferCHROMIUM(" << target << ")");
  GLuint buffer_id;
  if (!GetBoundPixelTransferBuffer(target, "glMapBufferCHROMIUM", &buffer_id)) {
    SetGLError(GL_INVALID_ENUM, "glUnmapBufferCHROMIUM", "invalid target");
  }
  if (!buffer_id) {
    return false;
  }
  BufferTracker::Buffer* buffer = buffer_tracker_->GetBuffer(buffer_id);
  if (!buffer) {
    SetGLError(GL_INVALID_OPERATION, "glUnmapBufferCHROMIUM", "invalid buffer");
    return false;
  }
  if (!buffer->mapped()) {
    SetGLError(GL_INVALID_OPERATION, "glUnmapBufferCHROMIUM", "not mapped");
    return false;
  }
  buffer->set_mapped(false);
  CheckGLError();
  return true;
}

uint64_t GLES2Implementation::ShareGroupTracingGUID() const {
  return share_group_->TracingGUID();
}

void GLES2Implementation::SetErrorMessageCallback(
    base::RepeatingCallback<void(const char*, int32_t)> callback) {
  error_message_callback_ = std::move(callback);
}

bool GLES2Implementation::ThreadSafeShallowLockDiscardableTexture(
    uint32_t texture_id) {
  ClientDiscardableTextureManager* manager =
      share_group()->discardable_texture_manager();
  return manager->TextureIsValid(texture_id) &&
         manager->LockTexture(texture_id);
}

void GLES2Implementation::CompleteLockDiscardableTexureOnContextThread(
    uint32_t texture_id) {
  helper_->LockDiscardableTextureCHROMIUM(texture_id);
}

bool GLES2Implementation::ThreadsafeDiscardableTextureIsDeletedForTracing(
    uint32_t texture_id) {
  ClientDiscardableTextureManager* manager =
      share_group()->discardable_texture_manager();
  return manager->TextureIsDeletedForTracing(texture_id);
}

void* GLES2Implementation::MapTransferCacheEntry(size_t serialized_size) {
  NOTREACHED();
  return nullptr;
}

void GLES2Implementation::UnmapAndCreateTransferCacheEntry(uint32_t type,
                                                           uint32_t id) {
  NOTREACHED();
}

bool GLES2Implementation::ThreadsafeLockTransferCacheEntry(uint32_t type,
                                                           uint32_t id) {
  NOTREACHED();
  return false;
}

void GLES2Implementation::UnlockTransferCacheEntries(
    const std::vector<std::pair<uint32_t, uint32_t>>& entries) {
  NOTREACHED();
}

void GLES2Implementation::DeleteTransferCacheEntry(uint32_t type, uint32_t id) {
  NOTREACHED();
}

unsigned int GLES2Implementation::GetTransferBufferFreeSize() const {
  NOTREACHED();
  return 0;
}

void GLES2Implementation::GenSyncTokenCHROMIUM(GLbyte* sync_token) {
  if (!sync_token) {
    SetGLError(GL_INVALID_VALUE, "glGenSyncTokenCHROMIUM", "empty sync_token");
    return;
  }

  uint64_t fence_sync = gpu_control_->GenerateFenceSyncRelease();
  helper_->InsertFenceSyncCHROMIUM(fence_sync);
  helper_->CommandBufferHelper::OrderingBarrier();
  gpu_control_->EnsureWorkVisible();

  // Copy the data over after setting the data to ensure alignment.
  SyncToken sync_token_data(gpu_control_->GetNamespaceID(),
                            gpu_control_->GetCommandBufferID(), fence_sync);
  sync_token_data.SetVerifyFlush();
  memcpy(sync_token, &sync_token_data, sizeof(sync_token_data));
}

void GLES2Implementation::GenUnverifiedSyncTokenCHROMIUM(GLbyte* sync_token) {
  if (!sync_token) {
    SetGLError(GL_INVALID_VALUE, "glGenUnverifiedSyncTokenCHROMIUM",
               "empty sync_token");
    return;
  }

  uint64_t fence_sync = gpu_control_->GenerateFenceSyncRelease();
  helper_->InsertFenceSyncCHROMIUM(fence_sync);
  helper_->CommandBufferHelper::OrderingBarrier();

  // Copy the data over after setting the data to ensure alignment.
  SyncToken sync_token_data(gpu_control_->GetNamespaceID(),
                            gpu_control_->GetCommandBufferID(), fence_sync);
  memcpy(sync_token, &sync_token_data, sizeof(sync_token_data));
}

void GLES2Implementation::VerifySyncTokensCHROMIUM(GLbyte **sync_tokens,
                                                   GLsizei count) {
  bool requires_synchronization = false;
  for (GLsizei i = 0; i < count; ++i) {
    if (sync_tokens[i]) {
      SyncToken sync_token;
      memcpy(&sync_token, sync_tokens[i], sizeof(sync_token));

      if (sync_token.HasData() && !sync_token.verified_flush()) {
        if (!GetVerifiedSyncTokenForIPC(sync_token, &sync_token)) {
          SetGLError(GL_INVALID_VALUE, "glVerifySyncTokensCHROMIUM",
                     "Cannot verify sync token using this context.");
          return;
        }
        requires_synchronization = true;
        DCHECK(sync_token.verified_flush());
      }

      // Set verify bit on empty sync tokens too.
      sync_token.SetVerifyFlush();

      memcpy(sync_tokens[i], &sync_token, sizeof(sync_token));
    }
  }

  // Ensure all the fence syncs are visible on GPU service.
  if (requires_synchronization)
    gpu_control_->EnsureWorkVisible();
}

void GLES2Implementation::WaitSyncTokenCHROMIUM(const GLbyte* sync_token_data) {
  if (!sync_token_data)
    return;

  // Copy the data over before data access to ensure alignment.
  SyncToken sync_token, verified_sync_token;
  memcpy(&sync_token, sync_token_data, sizeof(SyncToken));

  if (!sync_token.HasData())
    return;

  if (!GetVerifiedSyncTokenForIPC(sync_token, &verified_sync_token)) {
    SetGLError(GL_INVALID_VALUE, "glWaitSyncTokenCHROMIUM",
               "Cannot wait on sync_token which has not been verified");
    return;
  }

  helper_->WaitSyncTokenCHROMIUM(
      static_cast<GLint>(sync_token.namespace_id()),
      sync_token.command_buffer_id().GetUnsafeValue(),
      sync_token.release_count());

  // Enqueue sync token in flush after inserting command so that it's not
  // included in an automatic flush.
  gpu_control_->WaitSyncTokenHint(verified_sync_token);
}

namespace {

bool CreateImageValidInternalFormat(GLenum internalformat,
                                    const Capabilities& capabilities) {
  switch (internalformat) {
    case GL_ATC_RGB_AMD:
    case GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD:
      return capabilities.texture_format_atc;
    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
      return capabilities.texture_format_dxt1;
    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
      return capabilities.texture_format_dxt5;
    case GL_ETC1_RGB8_OES:
      return capabilities.texture_format_etc1;
    case GL_R16_EXT:
      return capabilities.texture_norm16;
    case GL_RGB10_A2_EXT:
      return capabilities.image_xr30 || capabilities.image_xb30;
    case GL_RED:
    case GL_RG_EXT:
    case GL_RGB:
    case GL_RGBA:
    case GL_RGB_YCBCR_422_CHROMIUM:
    case GL_RGB_YCBCR_420V_CHROMIUM:
    case GL_RGB_YCRCB_420_CHROMIUM:
    case GL_BGRA_EXT:
      return true;
    default:
      return false;
  }
}

}  // namespace

GLuint GLES2Implementation::CreateImageCHROMIUMHelper(ClientBuffer buffer,
                                                      GLsizei width,
                                                      GLsizei height,
                                                      GLenum internalformat) {
  if (width <= 0) {
    SetGLError(GL_INVALID_VALUE, "glCreateImageCHROMIUM", "width <= 0");
    return 0;
  }

  if (height <= 0) {
    SetGLError(GL_INVALID_VALUE, "glCreateImageCHROMIUM", "height <= 0");
    return 0;
  }

  if (!CreateImageValidInternalFormat(internalformat, capabilities_)) {
    SetGLError(GL_INVALID_VALUE, "glCreateImageCHROMIUM", "invalid format");
    return 0;
  }

  // CreateImage creates a fence sync so we must flush first to ensure all
  // previously created fence syncs are flushed first.
  FlushHelper();

  int32_t image_id =
      gpu_control_->CreateImage(buffer, width, height, internalformat);
  if (image_id < 0) {
    SetGLError(GL_OUT_OF_MEMORY, "glCreateImageCHROMIUM", "image_id < 0");
    return 0;
  }
  return image_id;
}

GLuint GLES2Implementation::CreateImageCHROMIUM(ClientBuffer buffer,
                                                GLsizei width,
                                                GLsizei height,
                                                GLenum internalformat) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCreateImageCHROMIUM(" << width
                     << ", " << height << ", "
                     << GLES2Util::GetStringImageInternalFormat(internalformat)
                     << ")");
  GLuint image_id =
      CreateImageCHROMIUMHelper(buffer, width, height, internalformat);
  CheckGLError();
  return image_id;
}

void GLES2Implementation::DestroyImageCHROMIUMHelper(GLuint image_id) {
  // Flush the command stream to make sure all pending commands
  // that may refer to the image_id are executed on the service side.
  helper_->CommandBufferHelper::Flush();
  gpu_control_->DestroyImage(image_id);
}

void GLES2Implementation::DestroyImageCHROMIUM(GLuint image_id) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDestroyImageCHROMIUM("
      << image_id << ")");
  DestroyImageCHROMIUMHelper(image_id);
  CheckGLError();
}

bool GLES2Implementation::ValidateSize(const char* func, GLsizeiptr size) {
  if (size < 0) {
    SetGLError(GL_INVALID_VALUE, func, "size < 0");
    return false;
  }
  if (!base::IsValueInRangeForNumericType<int32_t>(size)) {
    SetGLError(GL_INVALID_OPERATION, func, "size more than 32-bit");
    return false;
  }
  return true;
}

bool GLES2Implementation::ValidateOffset(const char* func, GLintptr offset) {
  if (offset < 0) {
    SetGLError(GL_INVALID_VALUE, func, "offset < 0");
    return false;
  }
  if (!base::IsValueInRangeForNumericType<int32_t>(offset)) {
    SetGLError(GL_INVALID_OPERATION, func, "offset more than 32-bit");
    return false;
  }
  return true;
}

bool GLES2Implementation::GetSamplerParameterfvHelper(
    GLuint /* sampler */, GLenum /* pname */, GLfloat* /* params */) {
  // TODO(zmo): Implement client side caching.
  return false;
}

bool GLES2Implementation::GetSamplerParameterivHelper(
    GLuint /* sampler */, GLenum /* pname */, GLint* /* params */) {
  // TODO(zmo): Implement client side caching.
  return false;
}

bool GLES2Implementation::PackStringsToBucket(GLsizei count,
                                              const char* const* str,
                                              const GLint* length,
                                              const char* func_name) {
  DCHECK_LE(0, count);
  // Compute the total size.
  base::CheckedNumeric<uint32_t> total_size = count;
  total_size += 1;
  total_size *= sizeof(GLint);
  if (!total_size.IsValid()) {
    SetGLError(GL_INVALID_VALUE, func_name, "overflow");
    return false;
  }
  size_t header_size = total_size.ValueOrDefault(0);
  std::vector<GLint> header(count + 1);
  header[0] = static_cast<GLint>(count);
  for (GLsizei ii = 0; ii < count; ++ii) {
    GLint len = 0;
    if (str[ii]) {
      len = (length && length[ii] >= 0)
                ? length[ii]
                : base::checked_cast<GLint>(strlen(str[ii]));
    }
    total_size += len;
    total_size += 1;  // NULL at the end of each char array.
    if (!total_size.IsValid()) {
      SetGLError(GL_INVALID_VALUE, func_name, "overflow");
      return false;
    }
    header[ii + 1] = len;
  }
  // Pack data into a bucket on the service.
  helper_->SetBucketSize(kResultBucketId, total_size.ValueOrDefault(0));
  size_t offset = 0;
  for (GLsizei ii = 0; ii <= count; ++ii) {
    const char* src =
        (ii == 0) ? reinterpret_cast<const char*>(&header[0]) : str[ii - 1];
    base::CheckedNumeric<size_t> checked_size =
        (ii == 0) ? header_size : static_cast<size_t>(header[ii]);
    if (ii > 0) {
      checked_size += 1;  // NULL in the end.
    }
    if (!checked_size.IsValid()) {
      SetGLError(GL_INVALID_VALUE, func_name, "overflow");
      return false;
    }
    size_t size = checked_size.ValueOrDefault(0);
    while (size) {
      ScopedTransferBufferPtr buffer(size, helper_, transfer_buffer_);
      if (!buffer.valid() || buffer.size() == 0) {
        SetGLError(GL_OUT_OF_MEMORY, func_name, "too large");
        return false;
      }
      size_t copy_size = buffer.size();
      if (ii > 0 && buffer.size() == size)
        --copy_size;
      if (copy_size)
        memcpy(buffer.address(), src, copy_size);
      if (copy_size < buffer.size()) {
        // Append NULL in the end.
        DCHECK(copy_size + 1 == buffer.size());
        char* str = reinterpret_cast<char*>(buffer.address());
        str[copy_size] = 0;
      }
      helper_->SetBucketData(kResultBucketId, offset, buffer.size(),
                             buffer.shm_id(), buffer.offset());
      offset += buffer.size();
      src += buffer.size();
      size -= buffer.size();
    }
  }
  DCHECK_EQ(total_size.ValueOrDefault(0), offset);
  return true;
}

void GLES2Implementation::UniformBlockBinding(GLuint program,
                                              GLuint index,
                                              GLuint binding) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glUniformBlockBinding(" << program
                     << ", " << index << ", " << binding << ")");
  share_group_->program_info_manager()->UniformBlockBinding(
      this, program, index, binding);
  helper_->UniformBlockBinding(program, index, binding);
  CheckGLError();
}

GLenum GLES2Implementation::ClientWaitSync(
    GLsync sync, GLbitfield flags, GLuint64 timeout) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glClientWaitSync(" << sync
                 << ", " << flags << ", " << timeout << ")");
  typedef cmds::ClientWaitSync::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    SetGLError(GL_OUT_OF_MEMORY, "ClientWaitSync", "");
    return GL_WAIT_FAILED;
  }
  *result = GL_WAIT_FAILED;
  helper_->ClientWaitSync(
      ToGLuint(sync), flags, timeout, GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  GPU_CLIENT_LOG("returned " << *result);
  CheckGLError();
  return *result;
}

void GLES2Implementation::CopyBufferSubData(GLenum readtarget,
                                            GLenum writetarget,
                                            GLintptr readoffset,
                                            GLintptr writeoffset,
                                            GLsizeiptr size) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCopyBufferSubData("
                     << GLES2Util::GetStringBufferTarget(readtarget) << ", "
                     << GLES2Util::GetStringBufferTarget(writetarget) << ", "
                     << readoffset << ", " << writeoffset << ", " << size
                     << ")");
  if (readoffset < 0) {
    SetGLError(GL_INVALID_VALUE, "glCopyBufferSubData", "readoffset < 0");
    return;
  }
  if (writeoffset < 0) {
    SetGLError(GL_INVALID_VALUE, "glCopyBufferSubData", "writeoffset < 0");
    return;
  }
  if (size < 0) {
    SetGLError(GL_INVALID_VALUE, "glCopyBufferSubData", "size < 0");
    return;
  }
  helper_->CopyBufferSubData(readtarget, writetarget, readoffset, writeoffset,
                             size);
  InvalidateReadbackBufferShadowDataCHROMIUM(GetBoundBufferHelper(writetarget));
  CheckGLError();
}

void GLES2Implementation::WaitSync(
    GLsync sync, GLbitfield flags, GLuint64 timeout) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glWaitSync(" << sync << ", "
                 << flags << ", " << timeout << ")");
  helper_->WaitSync(ToGLuint(sync), flags, timeout);
  CheckGLError();
}

void GLES2Implementation::GetInternalformativ(
    GLenum target, GLenum format, GLenum pname,
    GLsizei buf_size, GLint* params) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGetInternalformativ("
                     << GLES2Util::GetStringRenderBufferTarget(target) << ", "
                     << GLES2Util::GetStringRenderBufferFormat(format) << ", "
                     << GLES2Util::GetStringInternalFormatParameter(pname)
                     << ", " << buf_size << ", "
                     << static_cast<const void*>(params) << ")");
  if (buf_size < 0) {
    SetGLError(GL_INVALID_VALUE, "glGetInternalformativ", "bufSize < 0");
    return;
  }
  TRACE_EVENT0("gpu", "GLES2Implementation::GetInternalformativ");
  if (GetInternalformativHelper(target, format, pname, buf_size, params)) {
    return;
  }
  typedef cmds::GetInternalformativ::Result Result;
  Result* result = GetResultAs<Result*>();
  if (!result) {
    return;
  }
  result->SetNumResults(0);
  helper_->GetInternalformativ(target, format, pname,
                               GetResultShmId(), GetResultShmOffset());
  WaitForCmd();
  GPU_CLIENT_LOG_CODE_BLOCK({
    for (int32_t i = 0; i < result->GetNumResults(); ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << result->GetData()[i]);
    }
  });
  if (buf_size > 0 && params) {
    GLint* data = result->GetData();
    if (buf_size >= result->GetNumResults()) {
      buf_size = result->GetNumResults();
    }
    for (GLsizei ii = 0; ii < buf_size; ++ii) {
      params[ii] = data[ii];
    }
  }
  CheckGLError();
}

GLuint GLES2Implementation::GenPathsCHROMIUM(GLsizei range) {
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glGenPathsCHROMIUM(" << range
                     << ")");
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  static const char kFunctionName[] = "glGenPathsCHROMIUM";
  if (range < 0) {
    SetGLError(GL_INVALID_VALUE, kFunctionName, "range < 0");
    return 0;
  }
  if (!base::IsValueInRangeForNumericType<int32_t>(range)) {
    SetGLError(GL_INVALID_OPERATION, kFunctionName, "range more than 32-bit");
    return 0;
  }
  if (range == 0)
    return 0;

  GLuint first_client_id = 0;
  GetRangeIdHandler(id_namespaces::kPaths)
      ->MakeIdRange(this, range, &first_client_id);

  if (first_client_id == 0) {
    // Ran out of id space. Is not specified to raise any gl errors.
    return 0;
  }

  helper_->GenPathsCHROMIUM(first_client_id, range);

  GPU_CLIENT_LOG_CODE_BLOCK({
    for (GLsizei i = 0; i < range; ++i) {
      GPU_CLIENT_LOG("  " << i << ": " << (first_client_id + i));
    }
  });
  CheckGLError();
  return first_client_id;
}

void GLES2Implementation::DeletePathsCHROMIUM(GLuint first_client_id,
                                              GLsizei range) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glDeletePathsCHROMIUM("
                     << first_client_id << ", " << range << ")");
  static const char kFunctionName[] = "glDeletePathsCHROMIUM";

  if (range < 0) {
    SetGLError(GL_INVALID_VALUE, kFunctionName, "range < 0");
    return;
  }
  if (!base::IsValueInRangeForNumericType<int32_t>(range)) {
    SetGLError(GL_INVALID_OPERATION, kFunctionName, "range more than 32-bit");
    return;
  }
  if (range == 0)
    return;

  GLuint last_client_id;
  if (!SafeAddUint32(first_client_id, range - 1, &last_client_id)) {
    SetGLError(GL_INVALID_OPERATION, kFunctionName, "overflow");
    return;
  }

  GetRangeIdHandler(id_namespaces::kPaths)
      ->FreeIdRange(this, first_client_id, range,
                    &GLES2Implementation::DeletePathsCHROMIUMStub);
  CheckGLError();
}

void GLES2Implementation::DeletePathsCHROMIUMStub(GLuint first_client_id,
                                                  GLsizei range) {
  helper_->DeletePathsCHROMIUM(first_client_id, range);
}

void GLES2Implementation::PathCommandsCHROMIUM(GLuint path,
                                               GLsizei num_commands,
                                               const GLubyte* commands,
                                               GLsizei num_coords,
                                               GLenum coord_type,
                                               const void* coords) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glPathCommandsCHROMIUM(" << path
                     << ", " << num_commands << ", " << commands << ", "
                     << num_coords << ", " << coords << ")");
  static const char kFunctionName[] = "glPathCommandsCHROMIUM";
  if (path == 0) {
    SetGLError(GL_INVALID_VALUE, kFunctionName, "invalid path object");
    return;
  }
  if (num_commands < 0) {
    SetGLError(GL_INVALID_VALUE, kFunctionName, "numCommands < 0");
    return;
  }
  if (num_commands != 0 && !commands) {
    SetGLError(GL_INVALID_VALUE, kFunctionName, "missing commands");
    return;
  }
  if (num_coords < 0) {
    SetGLError(GL_INVALID_VALUE, kFunctionName, "numCoords < 0");
    return;
  }
  if (num_coords != 0 && !coords) {
    SetGLError(GL_INVALID_VALUE, kFunctionName, "missing coords");
    return;
  }
  uint32_t coord_type_size =
      GLES2Util::GetGLTypeSizeForPathCoordType(coord_type);
  if (coord_type_size == 0) {
    SetGLError(GL_INVALID_ENUM, kFunctionName, "invalid coordType");
    return;
  }
  if (num_commands == 0) {
    // No commands must mean no coords, thus nothing to memcpy. Let
    // the service validate the call. Validate coord_type above, so
    // that the parameters will be checked the in the same order
    // regardless of num_commands.
    helper_->PathCommandsCHROMIUM(path, num_commands, 0, 0, num_coords,
                                  coord_type, 0, 0);
    CheckGLError();
    return;
  }

  uint32_t coords_size;
  if (!SafeMultiplyUint32(num_coords, coord_type_size, &coords_size)) {
    SetGLError(GL_INVALID_OPERATION, kFunctionName, "overflow");
    return;
  }

  uint32_t required_buffer_size;
  if (!SafeAddUint32(coords_size, num_commands, &required_buffer_size)) {
    SetGLError(GL_INVALID_OPERATION, kFunctionName, "overflow");
    return;
  }

  ScopedTransferBufferPtr buffer(required_buffer_size, helper_,
                                 transfer_buffer_);
  if (!buffer.valid() || buffer.size() < required_buffer_size) {
    SetGLError(GL_OUT_OF_MEMORY, kFunctionName, "too large");
    return;
  }

  uint32_t coords_shm_id = 0;
  uint32_t coords_shm_offset = 0;
  // Copy coords first because they need more strict alignment.
  if (coords_size > 0) {
    unsigned char* coords_addr = static_cast<unsigned char*>(buffer.address());
    memcpy(coords_addr, coords, coords_size);
    coords_shm_id = buffer.shm_id();
    coords_shm_offset = buffer.offset();
  }

  DCHECK_GT(num_commands, 0);
  unsigned char* commands_addr =
      static_cast<unsigned char*>(buffer.address()) + coords_size;
  memcpy(commands_addr, commands, num_commands);

  helper_->PathCommandsCHROMIUM(path, num_commands, buffer.shm_id(),
                                buffer.offset() + coords_size, num_coords,
                                coord_type, coords_shm_id, coords_shm_offset);
  CheckGLError();
}

bool GLES2Implementation::PrepareInstancedPathCommand(
    const char* function_name,
    GLsizei num_paths,
    GLenum path_name_type,
    const void* paths,
    GLenum transform_type,
    const GLfloat* transform_values,
    ScopedTransferBufferPtr* buffer,
    uint32_t* out_paths_shm_id,
    size_t* out_paths_offset,
    uint32_t* out_transforms_shm_id,
    size_t* out_transforms_offset) {
  if (num_paths < 0) {
    SetGLError(GL_INVALID_VALUE, function_name, "numPaths < 0");
    return false;
  }
  uint32_t path_name_size =
      GLES2Util::GetGLTypeSizeForGLPathNameType(path_name_type);

  if (path_name_size == 0) {
    SetGLError(GL_INVALID_ENUM, function_name, "invalid pathNameType");
    return false;
  }

  uint32_t transforms_component_count =
      GLES2Util::GetComponentCountForGLTransformType(transform_type);

  if (transform_type != GL_NONE && transforms_component_count == 0) {
    SetGLError(GL_INVALID_ENUM, function_name, "invalid transformType");
    return false;
  }

  if (num_paths == 0) {
    // This might still be a valid or an invalid GL call. Make an empty call to
    // the service side to check the rest of the parameters. We check the above
    // parameters client-side, in order to get same GL errors whether num_paths
    // == 0 or not. We do not check the parameters below, as they are anyway
    // checked by the service side. We can not check all the parameters
    // client-side, since the validators are not available.
    *out_paths_shm_id = 0;
    *out_paths_offset = 0;
    *out_transforms_shm_id = 0;
    *out_transforms_offset = 0;
    return true;
  }

  if (!paths) {
    SetGLError(GL_INVALID_VALUE, function_name, "missing paths");
    return false;
  }

  if (transform_type != GL_NONE && !transform_values) {
    SetGLError(GL_INVALID_VALUE, function_name, "missing transforms");
    return false;
  }

  uint32_t paths_size;
  if (!SafeMultiplyUint32(path_name_size, num_paths, &paths_size)) {
    SetGLError(GL_INVALID_OPERATION, function_name, "overflow");
    return false;
  }

  // The multiplication below will not overflow.
  DCHECK_LE(transforms_component_count, 12U);
  uint32_t one_transform_size = sizeof(GLfloat) * transforms_component_count;

  uint32_t transforms_size;
  if (!SafeMultiplyUint32(one_transform_size, num_paths, &transforms_size)) {
    SetGLError(GL_INVALID_OPERATION, function_name, "overflow");
    return false;
  }

  uint32_t required_buffer_size;
  if (!SafeAddUint32(transforms_size, paths_size, &required_buffer_size)) {
    SetGLError(GL_INVALID_OPERATION, function_name, "overflow");
    return false;
  }

  buffer->Reset(required_buffer_size);

  if (!buffer->valid() || buffer->size() < required_buffer_size) {
    SetGLError(GL_OUT_OF_MEMORY, function_name, "too large");
    return false;
  }

  // Copy transforms first, they may have more strict alignment.
  if (transforms_size > 0) {
    unsigned char* transforms_addr =
        static_cast<unsigned char*>(buffer->address());
    memcpy(transforms_addr, transform_values, transforms_size);
    *out_transforms_shm_id = buffer->shm_id();
    *out_transforms_offset = buffer->offset();
  } else {
    *out_transforms_shm_id = 0;
    *out_transforms_offset = 0;
  }

  DCHECK_GT(paths_size, 0U);
  unsigned char* paths_addr =
      static_cast<unsigned char*>(buffer->address()) + transforms_size;
  memcpy(paths_addr, paths, paths_size);
  *out_paths_shm_id = buffer->shm_id();
  *out_paths_offset = buffer->offset() + transforms_size;

  return true;
}

void GLES2Implementation::StencilFillPathInstancedCHROMIUM(
    GLsizei num_paths,
    GLenum path_name_type,
    const GLvoid* paths,
    GLuint path_base,
    GLenum fill_mode,
    GLuint mask,
    GLenum transform_type,
    const GLfloat* transform_values) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix()
                     << "] glStencilFillPathInstancedCHROMIUM(" << num_paths
                     << ", " << path_name_type << ", " << paths << ", "
                     << path_base << ", " << fill_mode << ", " << mask << ", "
                     << transform_type << ", " << transform_values << ")");

  ScopedTransferBufferPtr buffer(helper_, transfer_buffer_);
  uint32_t paths_shm_id = 0;
  size_t paths_offset = 0;
  uint32_t transforms_shm_id = 0;
  size_t transforms_offset = 0;
  if (!PrepareInstancedPathCommand(
          "glStencilFillPathInstancedCHROMIUM", num_paths, path_name_type,
          paths, transform_type, transform_values, &buffer, &paths_shm_id,
          &paths_offset, &transforms_shm_id, &transforms_offset)) {
    return;
  }

  helper_->StencilFillPathInstancedCHROMIUM(
      num_paths, path_name_type, paths_shm_id, paths_offset, path_base,
      fill_mode, mask, transform_type, transforms_shm_id, transforms_offset);

  CheckGLError();
}

void GLES2Implementation::StencilStrokePathInstancedCHROMIUM(
    GLsizei num_paths,
    GLenum path_name_type,
    const GLvoid* paths,
    GLuint path_base,
    GLint ref,
    GLuint mask,
    GLenum transform_type,
    const GLfloat* transform_values) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix()
                     << "] glStencilStrokePathInstancedCHROMIUM(" << num_paths
                     << ", " << path_name_type << ", " << paths << ", "
                     << path_base << ", " << ref << ", " << mask << ", "
                     << transform_type << ", " << transform_values << ")");

  ScopedTransferBufferPtr buffer(helper_, transfer_buffer_);
  uint32_t paths_shm_id = 0;
  size_t paths_offset = 0;
  uint32_t transforms_shm_id = 0;
  size_t transforms_offset = 0;
  if (!PrepareInstancedPathCommand(
          "glStencilStrokePathInstancedCHROMIUM", num_paths, path_name_type,
          paths, transform_type, transform_values, &buffer, &paths_shm_id,
          &paths_offset, &transforms_shm_id, &transforms_offset)) {
    return;
  }

  helper_->StencilStrokePathInstancedCHROMIUM(
      num_paths, path_name_type, paths_shm_id, paths_offset, path_base, ref,
      mask, transform_type, transforms_shm_id, transforms_offset);

  CheckGLError();
}

void GLES2Implementation::CoverFillPathInstancedCHROMIUM(
    GLsizei num_paths,
    GLenum path_name_type,
    const GLvoid* paths,
    GLuint path_base,
    GLenum cover_mode,
    GLenum transform_type,
    const GLfloat* transform_values) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glCoverFillPathInstancedCHROMIUM("
                     << num_paths << ", " << path_name_type << ", " << paths
                     << ", " << path_base << ", " << cover_mode << ", "
                     << transform_type << ", " << transform_values << ")");

  ScopedTransferBufferPtr buffer(helper_, transfer_buffer_);
  uint32_t paths_shm_id = 0;
  size_t paths_offset = 0;
  uint32_t transforms_shm_id = 0;
  size_t transforms_offset = 0;
  if (!PrepareInstancedPathCommand(
          "glCoverFillPathInstancedCHROMIUM", num_paths, path_name_type, paths,
          transform_type, transform_values, &buffer, &paths_shm_id,
          &paths_offset, &transforms_shm_id, &transforms_offset)) {
    return;
  }

  helper_->CoverFillPathInstancedCHROMIUM(
      num_paths, path_name_type, paths_shm_id, paths_offset, path_base,
      cover_mode, transform_type, transforms_shm_id, transforms_offset);

  CheckGLError();
}

void GLES2Implementation::CoverStrokePathInstancedCHROMIUM(
    GLsizei num_paths,
    GLenum path_name_type,
    const GLvoid* paths,
    GLuint path_base,
    GLenum cover_mode,
    GLenum transform_type,
    const GLfloat* transform_values) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix()
                     << "] glCoverStrokePathInstancedCHROMIUM(" << num_paths
                     << ", " << path_name_type << ", " << paths << ", "
                     << path_base << ", " << cover_mode << ", "
                     << transform_type << ", " << transform_values << ")");

  ScopedTransferBufferPtr buffer(helper_, transfer_buffer_);
  uint32_t paths_shm_id = 0;
  size_t paths_offset = 0;
  uint32_t transforms_shm_id = 0;
  size_t transforms_offset = 0;
  if (!PrepareInstancedPathCommand(
          "glCoverStrokePathInstancedCHROMIUM", num_paths, path_name_type,
          paths, transform_type, transform_values, &buffer, &paths_shm_id,
          &paths_offset, &transforms_shm_id, &transforms_offset)) {
    return;
  }

  helper_->CoverStrokePathInstancedCHROMIUM(
      num_paths, path_name_type, paths_shm_id, paths_offset, path_base,
      cover_mode, transform_type, transforms_shm_id, transforms_offset);

  CheckGLError();
}

void GLES2Implementation::StencilThenCoverFillPathInstancedCHROMIUM(
    GLsizei num_paths,
    GLenum path_name_type,
    const GLvoid* paths,
    GLuint path_base,
    GLenum fill_mode,
    GLuint mask,
    GLenum cover_mode,
    GLenum transform_type,
    const GLfloat* transform_values) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG(
      "[" << GetLogPrefix() << "] glStencilThenCoverFillPathInstancedCHROMIUM("
          << num_paths << ", " << path_name_type << ", " << paths << ", "
          << path_base << ", " << cover_mode << ", " << fill_mode << ", "
          << mask << ", " << transform_type << ", " << transform_values << ")");

  ScopedTransferBufferPtr buffer(helper_, transfer_buffer_);
  uint32_t paths_shm_id = 0;
  size_t paths_offset = 0;
  uint32_t transforms_shm_id = 0;
  size_t transforms_offset = 0;
  if (!PrepareInstancedPathCommand(
          "glStencilThenCoverFillPathInstancedCHROMIUM", num_paths,
          path_name_type, paths, transform_type, transform_values, &buffer,
          &paths_shm_id, &paths_offset, &transforms_shm_id,
          &transforms_offset)) {
    return;
  }

  helper_->StencilThenCoverFillPathInstancedCHROMIUM(
      num_paths, path_name_type, paths_shm_id, paths_offset, path_base,
      fill_mode, mask, cover_mode, transform_type, transforms_shm_id,
      transforms_offset);

  CheckGLError();
}

void GLES2Implementation::StencilThenCoverStrokePathInstancedCHROMIUM(
    GLsizei num_paths,
    GLenum path_name_type,
    const GLvoid* paths,
    GLuint path_base,
    GLint ref,
    GLuint mask,
    GLenum cover_mode,
    GLenum transform_type,
    const GLfloat* transform_values) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix()
                     << "] glStencilThenCoverStrokePathInstancedCHROMIUM("
                     << num_paths << ", " << path_name_type << ", " << paths
                     << ", " << path_base << ", " << cover_mode << ", " << ref
                     << ", " << mask << ", " << transform_type << ", "
                     << transform_values << ")");

  ScopedTransferBufferPtr buffer(helper_, transfer_buffer_);
  uint32_t paths_shm_id = 0;
  size_t paths_offset = 0;
  uint32_t transforms_shm_id = 0;
  size_t transforms_offset = 0;
  if (!PrepareInstancedPathCommand(
          "glStencilThenCoverStrokePathInstancedCHROMIUM", num_paths,
          path_name_type, paths, transform_type, transform_values, &buffer,
          &paths_shm_id, &paths_offset, &transforms_shm_id,
          &transforms_offset)) {
    return;
  }

  helper_->StencilThenCoverStrokePathInstancedCHROMIUM(
      num_paths, path_name_type, paths_shm_id, paths_offset, path_base, ref,
      mask, cover_mode, transform_type, transforms_shm_id, transforms_offset);

  CheckGLError();
}

void GLES2Implementation::BindFragmentInputLocationCHROMIUM(GLuint program,
                                                            GLint location,
                                                            const char* name) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix()
                     << "] glBindFragmentInputLocationCHROMIUM(" << program
                     << ", " << location << ", " << name << ")");
  SetBucketAsString(kResultBucketId, name);
  helper_->BindFragmentInputLocationCHROMIUMBucket(program, location,
                                                   kResultBucketId);
  helper_->SetBucketSize(kResultBucketId, 0);
  CheckGLError();
}

void GLES2Implementation::ProgramPathFragmentInputGenCHROMIUM(
    GLuint program,
    GLint location,
    GLenum gen_mode,
    GLint components,
    const GLfloat* coeffs) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix()
                     << "] glProgramPathFragmentInputGenCHROMIUM(" << program
                     << ", " << gen_mode << ", " << components << ", " << coeffs
                     << ")");

  uint32_t coeffs_per_component =
      GLES2Util::GetCoefficientCountForGLPathFragmentInputGenMode(gen_mode);

  if (components <= 0 || components > 4 || gen_mode == GL_NONE ||
      coeffs_per_component == 0 || location == -1) {
    helper_->ProgramPathFragmentInputGenCHROMIUM(program, location, gen_mode,
                                                 components, 0, 0);
  } else {
    // The multiplication below will not overflow.
    DCHECK(coeffs_per_component > 0 && coeffs_per_component <= 4);
    DCHECK(components > 0 && components <= 4);
    uint32_t coeffs_size = sizeof(GLfloat) * coeffs_per_component * components;

    ScopedTransferBufferPtr buffer(coeffs_size, helper_, transfer_buffer_);
    if (!buffer.valid() || buffer.size() < coeffs_size) {
      SetGLError(GL_OUT_OF_MEMORY, "glProgramPathFragmentInputGenCHROMIUM",
                 "no room in transfer buffer");
      return;
    }

    DCHECK_GT(coeffs_size, 0U);
    unsigned char* addr = static_cast<unsigned char*>(buffer.address());
    memcpy(addr, coeffs, coeffs_size);

    helper_->ProgramPathFragmentInputGenCHROMIUM(program, location, gen_mode,
                                                 components, buffer.shm_id(),
                                                 buffer.offset());
  }
  CheckGLError();
}

void GLES2Implementation::InitializeDiscardableTextureCHROMIUM(
    GLuint texture_id) {
  ClientDiscardableTextureManager* manager =
      share_group()->discardable_texture_manager();
  if (manager->TextureIsValid(texture_id)) {
    SetGLError(GL_INVALID_VALUE, "glInitializeDiscardableTextureCHROMIUM",
               "Texture ID already initialized");
    return;
  }
  ClientDiscardableHandle handle =
      manager->InitializeTexture(helper_->command_buffer(), texture_id);
  if (!handle.IsValid())
    return;

  helper_->InitializeDiscardableTextureCHROMIUM(texture_id, handle.shm_id(),
                                                handle.byte_offset());
}

void GLES2Implementation::UnlockDiscardableTextureCHROMIUM(GLuint texture_id) {
  ClientDiscardableTextureManager* manager =
      share_group()->discardable_texture_manager();
  if (!manager->TextureIsValid(texture_id)) {
    SetGLError(GL_INVALID_VALUE, "glUnlockDiscardableTextureCHROMIUM",
               "Texture ID not initialized");
    return;
  }

  // |should_unbind_texture| will be set to true if the texture has been fully
  // unlocked. In this case, ensure the texture is unbound.
  bool should_unbind_texture = false;
  manager->UnlockTexture(texture_id, &should_unbind_texture);
  if (should_unbind_texture)
    UnbindTexturesHelper(1, &texture_id);

  helper_->UnlockDiscardableTextureCHROMIUM(texture_id);
}

bool GLES2Implementation::LockDiscardableTextureCHROMIUM(GLuint texture_id) {
  ClientDiscardableTextureManager* manager =
      share_group()->discardable_texture_manager();
  if (!manager->TextureIsValid(texture_id)) {
    SetGLError(GL_INVALID_VALUE, "glLockDiscardableTextureCHROMIUM",
               "Texture ID not initialized");
    return false;
  }
  if (!manager->LockTexture(texture_id)) {
    // Failure to lock means that this texture has been deleted on the service
    // side. Delete it here as well.
    DeleteTexturesHelper(1, &texture_id);
    return false;
  }
  helper_->LockDiscardableTextureCHROMIUM(texture_id);
  return true;
}

void GLES2Implementation::UpdateCachedExtensionsIfNeeded() {
  if (cached_extension_string_) {
    return;
  }
  GetStringHelper(GL_EXTENSIONS);
}

void GLES2Implementation::InvalidateCachedExtensions() {
  cached_extension_string_ = nullptr;
  cached_extensions_.clear();
}

void GLES2Implementation::Viewport(GLint x,
                                   GLint y,
                                   GLsizei width,
                                   GLsizei height) {
  GPU_CLIENT_SINGLE_THREAD_CHECK();
  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glViewport(" << x << ", " << y
                     << ", " << width << ", " << height << ")");
  if (width < 0 || height < 0) {
    SetGLError(GL_INVALID_VALUE, "glViewport", "negative width/height");
    return;
  }
  state_.SetViewport(x, y, width, height);
  helper_->Viewport(x, y, width, height);
  CheckGLError();
}

void GLES2Implementation::IssueBeginQuery(GLenum target,
                                          GLuint id,
                                          uint32_t sync_data_shm_id,
                                          uint32_t sync_data_shm_offset) {
  helper_->BeginQueryEXT(target, id, sync_data_shm_id, sync_data_shm_offset);
}

void GLES2Implementation::IssueEndQuery(GLenum target, GLuint submit_count) {
  helper_->EndQueryEXT(target, submit_count);
}

void GLES2Implementation::IssueQueryCounter(GLuint id,
                                            GLenum target,
                                            uint32_t sync_data_shm_id,
                                            uint32_t sync_data_shm_offset,
                                            GLuint submit_count) {
  helper_->QueryCounterEXT(id, target, sync_data_shm_id, sync_data_shm_offset,
                           submit_count);
}

void GLES2Implementation::IssueSetDisjointValueSync(
    uint32_t sync_data_shm_id,
    uint32_t sync_data_shm_offset) {
  helper_->SetDisjointValueSyncCHROMIUM(sync_data_shm_id, sync_data_shm_offset);
}

GLenum GLES2Implementation::GetClientSideGLError() {
  if (error_bits_ == 0) {
    return GL_NO_ERROR;
  }

  GLenum error = GL_NO_ERROR;
  for (uint32_t mask = 1; mask != 0; mask = mask << 1) {
    if ((error_bits_ & mask) != 0) {
      error = GLES2Util::GLErrorBitToGLError(mask);
      break;
    }
  }
  error_bits_ &= ~GLES2Util::GLErrorToErrorBit(error);
  return error;
}

CommandBufferHelper* GLES2Implementation::cmd_buffer_helper() {
  return helper_;
}

CommandBuffer* GLES2Implementation::command_buffer() const {
  return helper_->command_buffer();
}

// Include the auto-generated part of this file. We split this because it means
// we can easily edit the non-auto generated parts right here in this file
// instead of having to edit some template or the code generator.
#include "gpu/command_buffer/client/gles2_implementation_impl_autogen.h"

}  // namespace gles2
}  // namespace gpu