ui/gl/gl_surface_egl.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.

#include "ui/gl/gl_surface_egl.h"

#if defined(OS_ANDROID)
#include <android/native_window_jni.h>
#endif

#include "base/command_line.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/message_loop/message_loop.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gl/egl_util.h"
#include "ui/gl/gl_context.h"
#include "ui/gl/gl_implementation.h"
#include "ui/gl/gl_surface_stub.h"
#include "ui/gl/gl_switches.h"
#include "ui/gl/scoped_make_current.h"
#include "ui/gl/sync_control_vsync_provider.h"

#if defined(USE_X11)
extern "C" {
#include <X11/Xlib.h>
}
#endif

#if defined (USE_OZONE)
#include "ui/ozone/public/surface_factory_ozone.h"
#endif

#if !defined(EGL_FIXED_SIZE_ANGLE)
#define EGL_FIXED_SIZE_ANGLE 0x3201
#endif

#if !defined(EGL_OPENGL_ES3_BIT)
#define EGL_OPENGL_ES3_BIT 0x00000040
#endif

#if defined(OS_WIN)
// From ANGLE's egl/eglext.h.

#ifndef EGL_ANGLE_platform_angle
#define EGL_ANGLE_platform_angle 1
#define EGL_PLATFORM_ANGLE_ANGLE 0x3202
#define EGL_PLATFORM_ANGLE_TYPE_ANGLE 0x3203
#define EGL_PLATFORM_ANGLE_MAX_VERSION_MAJOR_ANGLE 0x3204
#define EGL_PLATFORM_ANGLE_MAX_VERSION_MINOR_ANGLE 0x3205
#define EGL_PLATFORM_ANGLE_TYPE_DEFAULT_ANGLE 0x3206
#endif /* EGL_ANGLE_platform_angle */

#ifndef EGL_ANGLE_platform_angle_d3d
#define EGL_ANGLE_platform_angle_d3d 1
#define EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE 0x3207
#define EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE 0x3208
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE 0x3209
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_HARDWARE_ANGLE 0x320A
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_WARP_ANGLE 0x320B
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_REFERENCE_ANGLE 0x320C
#endif /* EGL_ANGLE_platform_angle_d3d */

#endif  // defined(OS_WIN)

using ui::GetLastEGLErrorString;

namespace gfx {

#if defined(OS_WIN)
unsigned int NativeViewGLSurfaceEGL::current_swap_generation_ = 0;
unsigned int NativeViewGLSurfaceEGL::swaps_this_generation_ = 0;
unsigned int NativeViewGLSurfaceEGL::last_multiswap_generation_ = 0;

const unsigned int MULTISWAP_FRAME_VSYNC_THRESHOLD = 60;
#endif

namespace {

EGLConfig g_config;
EGLDisplay g_display;
EGLNativeDisplayType g_native_display_type;

// In the Cast environment, we need to destroy the EGLNativeDisplayType and
// EGLDisplay returned by the GPU platform when we switch to an external app
// which will temporarily own all screen and GPU resources.
// Even though Chromium is still in the background.
// As such, it must be reinitialized each time we come back to the foreground.
bool g_initialized = false;
int g_num_surfaces = 0;
bool g_terminate_pending = false;

const char* g_egl_extensions = NULL;
bool g_egl_create_context_robustness_supported = false;
bool g_egl_sync_control_supported = false;
bool g_egl_window_fixed_size_supported = false;
bool g_egl_surfaceless_context_supported = false;

class EGLSyncControlVSyncProvider
    : public gfx::SyncControlVSyncProvider {
 public:
  explicit EGLSyncControlVSyncProvider(EGLSurface surface)
      : SyncControlVSyncProvider(),
        surface_(surface) {
  }

  ~EGLSyncControlVSyncProvider() override {}

 protected:
  bool GetSyncValues(int64* system_time,
                     int64* media_stream_counter,
                     int64* swap_buffer_counter) override {
    uint64 u_system_time, u_media_stream_counter, u_swap_buffer_counter;
    bool result = eglGetSyncValuesCHROMIUM(
        g_display, surface_, &u_system_time,
        &u_media_stream_counter, &u_swap_buffer_counter) == EGL_TRUE;
    if (result) {
      *system_time = static_cast<int64>(u_system_time);
      *media_stream_counter = static_cast<int64>(u_media_stream_counter);
      *swap_buffer_counter = static_cast<int64>(u_swap_buffer_counter);
    }
    return result;
  }

  bool GetMscRate(int32* numerator, int32* denominator) override {
    return false;
  }

 private:
  EGLSurface surface_;

  DISALLOW_COPY_AND_ASSIGN(EGLSyncControlVSyncProvider);
};

void DeinitializeEgl() {
  if (g_initialized) {
    g_initialized = false;
    eglTerminate(g_display);
  }
}

}  // namespace

GLSurfaceEGL::GLSurfaceEGL() {
  ++g_num_surfaces;
  if (!g_initialized) {
    bool result = GLSurfaceEGL::InitializeOneOff();
    DCHECK(result);
    DCHECK(g_initialized);
  }
}

bool GLSurfaceEGL::InitializeOneOff() {
  if (g_initialized)
    return true;

  g_native_display_type = GetPlatformDefaultEGLNativeDisplay();

#if defined(OS_WIN)
  g_display = GetPlatformDisplay(g_native_display_type);
#else
  g_display = eglGetDisplay(g_native_display_type);
#endif

  if (!g_display) {
    LOG(ERROR) << "eglGetDisplay failed with error " << GetLastEGLErrorString();
    return false;
  }

  if (!eglInitialize(g_display, NULL, NULL)) {
    LOG(ERROR) << "eglInitialize failed with error " << GetLastEGLErrorString();
    return false;
  }

  // Choose an EGL configuration.
  // On X this is only used for PBuffer surfaces.
  EGLint renderable_type = EGL_OPENGL_ES2_BIT;
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kEnableUnsafeES3APIs)) {
    renderable_type = EGL_OPENGL_ES3_BIT;
  }
  const EGLint kConfigAttribs[] = {
    EGL_BUFFER_SIZE, 32,
    EGL_ALPHA_SIZE, 8,
    EGL_BLUE_SIZE, 8,
    EGL_GREEN_SIZE, 8,
    EGL_RED_SIZE, 8,
    EGL_RENDERABLE_TYPE, renderable_type,
    EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT,
    EGL_NONE
  };

#if defined(USE_OZONE)
  const EGLint* config_attribs =
      ui::SurfaceFactoryOzone::GetInstance()->GetEGLSurfaceProperties(
          kConfigAttribs);
#else
  const EGLint* config_attribs = kConfigAttribs;
#endif

  EGLint num_configs;
  if (!eglChooseConfig(g_display,
                       config_attribs,
                       NULL,
                       0,
                       &num_configs)) {
    LOG(ERROR) << "eglChooseConfig failed with error "
               << GetLastEGLErrorString();
    return false;
  }

  if (num_configs == 0) {
    LOG(ERROR) << "No suitable EGL configs found.";
    return false;
  }

  if (!eglChooseConfig(g_display,
                       config_attribs,
                       &g_config,
                       1,
                       &num_configs)) {
    LOG(ERROR) << "eglChooseConfig failed with error "
               << GetLastEGLErrorString();
    return false;
  }

  g_egl_extensions = eglQueryString(g_display, EGL_EXTENSIONS);
  g_egl_create_context_robustness_supported =
      HasEGLExtension("EGL_EXT_create_context_robustness");
  g_egl_sync_control_supported =
      HasEGLExtension("EGL_CHROMIUM_sync_control");
  g_egl_window_fixed_size_supported =
      HasEGLExtension("EGL_ANGLE_window_fixed_size");

  // We always succeed beyond this point so set g_initialized here to avoid
  // infinite recursion through CreateGLContext and GetDisplay
  // if g_egl_surfaceless_context_supported.
  g_initialized = true;
  g_terminate_pending = false;

  // TODO(oetuaho@nvidia.com): Surfaceless is disabled on Android as a temporary
  // workaround, since code written for Android WebView takes different paths
  // based on whether GL surface objects have underlying EGL surface handles,
  // conflicting with the use of surfaceless. See https://crbug.com/382349
#if defined(OS_ANDROID)
  DCHECK(!g_egl_surfaceless_context_supported);
#else
  // Check if SurfacelessEGL is supported.
  g_egl_surfaceless_context_supported =
      HasEGLExtension("EGL_KHR_surfaceless_context");
  if (g_egl_surfaceless_context_supported) {
    // EGL_KHR_surfaceless_context is supported but ensure
    // GL_OES_surfaceless_context is also supported. We need a current context
    // to query for supported GL extensions.
    scoped_refptr<GLSurface> surface = new SurfacelessEGL(Size(1, 1));
    scoped_refptr<GLContext> context = GLContext::CreateGLContext(
      NULL, surface.get(), PreferIntegratedGpu);
    if (!context->MakeCurrent(surface.get()))
      g_egl_surfaceless_context_supported = false;

    // Ensure context supports GL_OES_surfaceless_context.
    if (g_egl_surfaceless_context_supported) {
      g_egl_surfaceless_context_supported = context->HasExtension(
          "GL_OES_surfaceless_context");
      context->ReleaseCurrent(surface.get());
    }
  }
#endif

  return true;
}

EGLDisplay GLSurfaceEGL::GetDisplay() {
  DCHECK(g_initialized);
  return g_display;
}

// static
EGLDisplay GLSurfaceEGL::GetHardwareDisplay() {
  if (!g_initialized) {
    bool result = GLSurfaceEGL::InitializeOneOff();
    DCHECK(result);
  }
  return g_display;
}

// static
EGLNativeDisplayType GLSurfaceEGL::GetNativeDisplay() {
  if (!g_initialized) {
    bool result = GLSurfaceEGL::InitializeOneOff();
    DCHECK(result);
  }
  return g_native_display_type;
}

const char* GLSurfaceEGL::GetEGLExtensions() {
  // No need for InitializeOneOff. Assume that extensions will not change
  // after the first initialization.
  return g_egl_extensions;
}

bool GLSurfaceEGL::HasEGLExtension(const char* name) {
  return ExtensionsContain(GetEGLExtensions(), name);
}

bool GLSurfaceEGL::IsCreateContextRobustnessSupported() {
  return g_egl_create_context_robustness_supported;
}

bool GLSurfaceEGL::IsEGLSurfacelessContextSupported() {
  return g_egl_surfaceless_context_supported;
}

void GLSurfaceEGL::DestroyAndTerminateDisplay() {
  DCHECK(g_initialized);
  DCHECK_EQ(g_num_surfaces, 1);
  Destroy();
  g_terminate_pending = true;
}

GLSurfaceEGL::~GLSurfaceEGL() {
  DCHECK_GT(g_num_surfaces, 0) << "Bad surface count";
  if (--g_num_surfaces == 0 && g_terminate_pending) {
    DeinitializeEgl();
    g_terminate_pending = false;
  }
}

#if defined(OS_WIN)
static const EGLint kDisplayAttribsWarp[] {
  EGL_PLATFORM_ANGLE_TYPE_ANGLE,
  EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE,

  EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE,
  EGL_PLATFORM_ANGLE_DEVICE_TYPE_WARP_ANGLE,

  EGL_NONE
};

// static
EGLDisplay GLSurfaceEGL::GetPlatformDisplay(
    EGLNativeDisplayType native_display) {
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseWarp)) {
    // Check for availability of WARP via ANGLE extension.
    bool supports_warp = false;
    const char* no_display_extensions = eglQueryString(EGL_NO_DISPLAY,
        EGL_EXTENSIONS);
    // If EGL_EXT_client_extensions not supported this call to eglQueryString
    // will return NULL.
    if (no_display_extensions)
      supports_warp =
          ExtensionsContain(no_display_extensions, "ANGLE_platform_angle") &&
          ExtensionsContain(no_display_extensions, "ANGLE_platform_angle_d3d");

    if (!supports_warp)
      return NULL;

    return eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, native_display,
        kDisplayAttribsWarp);
  }

  return eglGetDisplay(native_display);
}
#endif

NativeViewGLSurfaceEGL::NativeViewGLSurfaceEGL(EGLNativeWindowType window)
    : window_(window),
      surface_(NULL),
      supports_post_sub_buffer_(false),
      config_(NULL),
      size_(1, 1),
      swap_interval_(1) {
#if defined(OS_ANDROID)
  if (window)
    ANativeWindow_acquire(window);
#endif

#if defined(OS_WIN)
  vsync_override_ = false;
  swap_generation_ = 0;
  RECT windowRect;
  if (GetClientRect(window_, &windowRect))
    size_ = gfx::Rect(windowRect).size();
#endif
}

bool NativeViewGLSurfaceEGL::Initialize() {
  return Initialize(nullptr);
}

bool NativeViewGLSurfaceEGL::Initialize(
    scoped_ptr<VSyncProvider> sync_provider) {
  DCHECK(!surface_);

  if (!GetDisplay()) {
    LOG(ERROR) << "Trying to create surface with invalid display.";
    return false;
  }

  std::vector<EGLint> egl_window_attributes;

  if (g_egl_window_fixed_size_supported) {
    egl_window_attributes.push_back(EGL_FIXED_SIZE_ANGLE);
    egl_window_attributes.push_back(EGL_TRUE);
    egl_window_attributes.push_back(EGL_WIDTH);
    egl_window_attributes.push_back(size_.width());
    egl_window_attributes.push_back(EGL_HEIGHT);
    egl_window_attributes.push_back(size_.height());
  }

  if (gfx::g_driver_egl.ext.b_EGL_NV_post_sub_buffer) {
    egl_window_attributes.push_back(EGL_POST_SUB_BUFFER_SUPPORTED_NV);
    egl_window_attributes.push_back(EGL_TRUE);
  }

  egl_window_attributes.push_back(EGL_NONE);
  // Create a surface for the native window.
  surface_ = eglCreateWindowSurface(
      GetDisplay(), GetConfig(), window_, &egl_window_attributes[0]);

  if (!surface_) {
    LOG(ERROR) << "eglCreateWindowSurface failed with error "
               << GetLastEGLErrorString();
    Destroy();
    return false;
  }

  if (gfx::g_driver_egl.ext.b_EGL_NV_post_sub_buffer) {
    EGLint surfaceVal;
    EGLBoolean retVal = eglQuerySurface(
        GetDisplay(), surface_, EGL_POST_SUB_BUFFER_SUPPORTED_NV, &surfaceVal);
    supports_post_sub_buffer_ = (surfaceVal && retVal) == EGL_TRUE;
  }

  if (sync_provider)
    vsync_provider_.reset(sync_provider.release());
  else if (g_egl_sync_control_supported)
    vsync_provider_.reset(new EGLSyncControlVSyncProvider(surface_));
  return true;
}

void NativeViewGLSurfaceEGL::Destroy() {
  if (surface_) {
    if (!eglDestroySurface(GetDisplay(), surface_)) {
      LOG(ERROR) << "eglDestroySurface failed with error "
                 << GetLastEGLErrorString();
    }
    surface_ = NULL;
  }
}

EGLConfig NativeViewGLSurfaceEGL::GetConfig() {
#if !defined(USE_X11)
  return g_config;
#else
  if (!config_) {
    // Get a config compatible with the window
    DCHECK(window_);
    XWindowAttributes win_attribs;
    if (!XGetWindowAttributes(GetNativeDisplay(), window_, &win_attribs)) {
      return NULL;
    }

    // Try matching the window depth with an alpha channel,
    // because we're worried the destination alpha width could
    // constrain blending precision.
    const int kBufferSizeOffset = 1;
    const int kAlphaSizeOffset = 3;
    EGLint config_attribs[] = {
      EGL_BUFFER_SIZE, ~0,
      EGL_ALPHA_SIZE, 8,
      EGL_BLUE_SIZE, 8,
      EGL_GREEN_SIZE, 8,
      EGL_RED_SIZE, 8,
      EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
      EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT,
      EGL_NONE
    };
    config_attribs[kBufferSizeOffset] = win_attribs.depth;

    EGLint num_configs;
    if (!eglChooseConfig(g_display,
                         config_attribs,
                         &config_,
                         1,
                         &num_configs)) {
      LOG(ERROR) << "eglChooseConfig failed with error "
                 << GetLastEGLErrorString();
      return NULL;
    }

    if (num_configs) {
      EGLint config_depth;
      if (!eglGetConfigAttrib(g_display,
                              config_,
                              EGL_BUFFER_SIZE,
                              &config_depth)) {
        LOG(ERROR) << "eglGetConfigAttrib failed with error "
                   << GetLastEGLErrorString();
        return NULL;
      }

      if (config_depth == win_attribs.depth) {
        return config_;
      }
    }

    // Try without an alpha channel.
    config_attribs[kAlphaSizeOffset] = 0;
    if (!eglChooseConfig(g_display,
                         config_attribs,
                         &config_,
                         1,
                         &num_configs)) {
      LOG(ERROR) << "eglChooseConfig failed with error "
                 << GetLastEGLErrorString();
      return NULL;
    }

    if (num_configs == 0) {
      LOG(ERROR) << "No suitable EGL configs found.";
      return NULL;
    }
  }
  return config_;
#endif
}

bool NativeViewGLSurfaceEGL::IsOffscreen() {
  return false;
}

bool NativeViewGLSurfaceEGL::SwapBuffers() {
  TRACE_EVENT2("gpu", "NativeViewGLSurfaceEGL:RealSwapBuffers",
      "width", GetSize().width(),
      "height", GetSize().height());

#if defined(OS_WIN)
  if (swap_interval_ != 0) {
    // This code is a simple way of enforcing that we only vsync if one surface
    // is swapping per frame. This provides single window cases a stable refresh
    // while allowing multi-window cases to not slow down due to multiple syncs
    // on a single thread. A better way to fix this problem would be to have
    // each surface present on its own thread.

    if (current_swap_generation_ == swap_generation_) {
      if (swaps_this_generation_ > 1)
        last_multiswap_generation_ = current_swap_generation_;
      swaps_this_generation_ = 0;
      current_swap_generation_++;
    }

    swap_generation_ = current_swap_generation_;

    if (swaps_this_generation_ != 0 ||
        (current_swap_generation_ - last_multiswap_generation_ <
            MULTISWAP_FRAME_VSYNC_THRESHOLD)) {
      // Override vsync settings and switch it off
      if (!vsync_override_) {
        eglSwapInterval(GetDisplay(), 0);
        vsync_override_ = true;
      }
    } else if (vsync_override_) {
      // Only one window swapping, so let the normal vsync setting take over
      eglSwapInterval(GetDisplay(), swap_interval_);
      vsync_override_ = false;
    }

    swaps_this_generation_++;
  }
#endif

  if (!eglSwapBuffers(GetDisplay(), surface_)) {
    DVLOG(1) << "eglSwapBuffers failed with error "
             << GetLastEGLErrorString();
    return false;
  }

  return true;
}

gfx::Size NativeViewGLSurfaceEGL::GetSize() {
  EGLint width;
  EGLint height;
  if (!eglQuerySurface(GetDisplay(), surface_, EGL_WIDTH, &width) ||
      !eglQuerySurface(GetDisplay(), surface_, EGL_HEIGHT, &height)) {
    NOTREACHED() << "eglQuerySurface failed with error "
                 << GetLastEGLErrorString();
    return gfx::Size();
  }

  return gfx::Size(width, height);
}

bool NativeViewGLSurfaceEGL::Resize(const gfx::Size& size) {
  if (size == GetSize())
    return true;

  size_ = size;

  scoped_ptr<ui::ScopedMakeCurrent> scoped_make_current;
  GLContext* current_context = GLContext::GetCurrent();
  bool was_current =
      current_context && current_context->IsCurrent(this);
  if (was_current) {
    scoped_make_current.reset(
        new ui::ScopedMakeCurrent(current_context, this));
    current_context->ReleaseCurrent(this);
  }

  Destroy();

  if (!Initialize()) {
    LOG(ERROR) << "Failed to resize window.";
    return false;
  }

  return true;
}

bool NativeViewGLSurfaceEGL::Recreate() {
  Destroy();
  if (!Initialize()) {
    LOG(ERROR) << "Failed to create surface.";
    return false;
  }
  return true;
}

EGLSurface NativeViewGLSurfaceEGL::GetHandle() {
  return surface_;
}

bool NativeViewGLSurfaceEGL::SupportsPostSubBuffer() {
  return supports_post_sub_buffer_;
}

bool NativeViewGLSurfaceEGL::PostSubBuffer(
    int x, int y, int width, int height) {
  DCHECK(supports_post_sub_buffer_);
  if (!eglPostSubBufferNV(GetDisplay(), surface_, x, y, width, height)) {
    DVLOG(1) << "eglPostSubBufferNV failed with error "
             << GetLastEGLErrorString();
    return false;
  }
  return true;
}

VSyncProvider* NativeViewGLSurfaceEGL::GetVSyncProvider() {
  return vsync_provider_.get();
}

void NativeViewGLSurfaceEGL::OnSetSwapInterval(int interval) {
  swap_interval_ = interval;
}

NativeViewGLSurfaceEGL::~NativeViewGLSurfaceEGL() {
  Destroy();
#if defined(OS_ANDROID)
  if (window_)
    ANativeWindow_release(window_);
#endif
}

PbufferGLSurfaceEGL::PbufferGLSurfaceEGL(const gfx::Size& size)
    : size_(size),
      surface_(NULL) {
  // Some implementations of Pbuffer do not support having a 0 size. For such
  // cases use a (1, 1) surface.
  if (size_.GetArea() == 0)
    size_.SetSize(1, 1);
}

bool PbufferGLSurfaceEGL::Initialize() {
  EGLSurface old_surface = surface_;

  EGLDisplay display = GetDisplay();
  if (!display) {
    LOG(ERROR) << "Trying to create surface with invalid display.";
    return false;
  }

  // Allocate the new pbuffer surface before freeing the old one to ensure
  // they have different addresses. If they have the same address then a
  // future call to MakeCurrent might early out because it appears the current
  // context and surface have not changed.
  const EGLint pbuffer_attribs[] = {
    EGL_WIDTH, size_.width(),
    EGL_HEIGHT, size_.height(),
    EGL_NONE
  };

  EGLSurface new_surface = eglCreatePbufferSurface(display,
                                                   GetConfig(),
                                                   pbuffer_attribs);
  if (!new_surface) {
    LOG(ERROR) << "eglCreatePbufferSurface failed with error "
               << GetLastEGLErrorString();
    return false;
  }

  if (old_surface)
    eglDestroySurface(display, old_surface);

  surface_ = new_surface;
  return true;
}

void PbufferGLSurfaceEGL::Destroy() {
  if (surface_) {
    if (!eglDestroySurface(GetDisplay(), surface_)) {
      LOG(ERROR) << "eglDestroySurface failed with error "
                 << GetLastEGLErrorString();
    }
    surface_ = NULL;
  }
}

EGLConfig PbufferGLSurfaceEGL::GetConfig() {
  return g_config;
}

bool PbufferGLSurfaceEGL::IsOffscreen() {
  return true;
}

bool PbufferGLSurfaceEGL::SwapBuffers() {
  NOTREACHED() << "Attempted to call SwapBuffers on a PbufferGLSurfaceEGL.";
  return false;
}

gfx::Size PbufferGLSurfaceEGL::GetSize() {
  return size_;
}

bool PbufferGLSurfaceEGL::Resize(const gfx::Size& size) {
  if (size == size_)
    return true;

  scoped_ptr<ui::ScopedMakeCurrent> scoped_make_current;
  GLContext* current_context = GLContext::GetCurrent();
  bool was_current =
      current_context && current_context->IsCurrent(this);
  if (was_current) {
    scoped_make_current.reset(
        new ui::ScopedMakeCurrent(current_context, this));
  }

  size_ = size;

  if (!Initialize()) {
    LOG(ERROR) << "Failed to resize pbuffer.";
    return false;
  }

  return true;
}

EGLSurface PbufferGLSurfaceEGL::GetHandle() {
  return surface_;
}

void* PbufferGLSurfaceEGL::GetShareHandle() {
#if defined(OS_ANDROID)
  NOTREACHED();
  return NULL;
#else
  if (!gfx::g_driver_egl.ext.b_EGL_ANGLE_query_surface_pointer)
    return NULL;

  if (!gfx::g_driver_egl.ext.b_EGL_ANGLE_surface_d3d_texture_2d_share_handle)
    return NULL;

  void* handle;
  if (!eglQuerySurfacePointerANGLE(g_display,
                                   GetHandle(),
                                   EGL_D3D_TEXTURE_2D_SHARE_HANDLE_ANGLE,
                                   &handle)) {
    return NULL;
  }

  return handle;
#endif
}

PbufferGLSurfaceEGL::~PbufferGLSurfaceEGL() {
  Destroy();
}

SurfacelessEGL::SurfacelessEGL(const gfx::Size& size)
    : size_(size) {
}

bool SurfacelessEGL::Initialize() {
  return true;
}

void SurfacelessEGL::Destroy() {
}

EGLConfig SurfacelessEGL::GetConfig() {
  return g_config;
}

bool SurfacelessEGL::IsOffscreen() {
  return true;
}

bool SurfacelessEGL::IsSurfaceless() const {
  return true;
}

bool SurfacelessEGL::SwapBuffers() {
  LOG(ERROR) << "Attempted to call SwapBuffers with SurfacelessEGL.";
  return false;
}

gfx::Size SurfacelessEGL::GetSize() {
  return size_;
}

bool SurfacelessEGL::Resize(const gfx::Size& size) {
  size_ = size;
  return true;
}

EGLSurface SurfacelessEGL::GetHandle() {
  return EGL_NO_SURFACE;
}

void* SurfacelessEGL::GetShareHandle() {
  return NULL;
}

SurfacelessEGL::~SurfacelessEGL() {
}

}  // namespace gfx