gpu/command_buffer/tests/gl_texture_mailbox_unittest.cc - chromium/src - Git at Google

 // Copyright 2014 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 <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <GLES2/gl2extchromium.h>
 #include <stddef.h>
 #include <stdint.h>

 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "gpu/command_buffer/client/gles2_lib.h"
 #include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 #include "gpu/command_buffer/service/mailbox_manager.h"
 #include "gpu/command_buffer/tests/gl_manager.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gl/gl_share_group.h"

 namespace gpu {

 namespace {
 uint32_t ReadTexel(GLuint id, GLint x, GLint y) {
   GLint old_fbo = 0;
   glGetIntegerv(GL_FRAMEBUFFER_BINDING, &old_fbo);

   GLuint fbo;
   glGenFramebuffers(1, &fbo);
   glBindFramebuffer(GL_FRAMEBUFFER, fbo);
   glFramebufferTexture2D(GL_FRAMEBUFFER,
                          GL_COLOR_ATTACHMENT0,
                          GL_TEXTURE_2D,
                          id,
                          0);
   // Some drivers (NVidia/SGX) require texture settings to be a certain way or
   // they won't report FRAMEBUFFER_COMPLETE.
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

   EXPECT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
             glCheckFramebufferStatus(GL_FRAMEBUFFER));

   uint32_t texel = 0;
   glReadPixels(x, y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &texel);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   glBindFramebuffer(GL_FRAMEBUFFER, old_fbo);

   glDeleteFramebuffers(1, &fbo);

   return texel;
 }
 }

 class GLTextureMailboxTest : public testing::Test {
  protected:
   void SetUpContexts() {
     gl1_.Initialize(GLManager::Options());
     GLManager::Options options;
     options.share_mailbox_manager = &gl1_;
     gl2_.Initialize(options);
   }

   void TearDown() override {
     gl1_.Destroy();
     gl2_.Destroy();
   }

   // The second GL context takes and consumes a mailbox from the first GL
   // context. Assumes that |gl1_| is current.
   Mailbox TakeAndConsumeMailbox() {
     glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
     glClearColor(0, 1, 1, 1);
     glClear(GL_COLOR_BUFFER_BIT);
     ::gles2::GetGLContext()->SwapBuffers(1);

     Mailbox mailbox = Mailbox::Generate();
     gl1_.decoder()->TakeFrontBuffer(mailbox);

     gl2_.MakeCurrent();
     GLuint tex = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
     glBindTexture(GL_TEXTURE_2D, tex);
     glDeleteTextures(1, &tex);
     glFlush();
     gl1_.MakeCurrent();
     return mailbox;
   }

   void AllocateTextureBackedFramebuffer(GLuint* tex, GLuint* fbo) {
     glGenTextures(1, tex);
     glBindTexture(GL_TEXTURE_2D, *tex);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                  nullptr);
     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     glGenFramebuffers(1, fbo);
     glBindFramebuffer(GL_FRAMEBUFFER, *fbo);
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                            *tex, 0);
     ASSERT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
               glCheckFramebufferStatus(GL_FRAMEBUFFER));
   }

   GLManager gl1_;
   GLManager gl2_;
 };

 TEST_F(GLTextureMailboxTest, ProduceAndConsumeTexture) {
   SetUpContexts();
   gl1_.MakeCurrent();

   GLuint tex1;
   glGenTextures(1, &tex1);

   glBindTexture(GL_TEXTURE_2D, tex1);
   uint32_t source_pixel = 0xFF0000FF;
   glTexImage2D(GL_TEXTURE_2D,
                0,
                GL_RGBA,
                1, 1,
                0,
                GL_RGBA,
                GL_UNSIGNED_BYTE,
                &source_pixel);

   GLbyte mailbox1[GL_MAILBOX_SIZE_CHROMIUM];
   glProduceTextureDirectCHROMIUM(tex1, mailbox1);
   glFlush();

   gl2_.MakeCurrent();

   GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox1);
   glBindTexture(GL_TEXTURE_2D, tex2);
   EXPECT_EQ(source_pixel, ReadTexel(tex2, 0, 0));
   GLbyte mailbox2[GL_MAILBOX_SIZE_CHROMIUM];
   glProduceTextureDirectCHROMIUM(tex2, mailbox2);
   glFlush();

   gl1_.MakeCurrent();

   tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox2);
   glBindTexture(GL_TEXTURE_2D, tex1);
   EXPECT_EQ(source_pixel, ReadTexel(tex1, 0, 0));
 }

 TEST_F(GLTextureMailboxTest, ProduceAndConsumeTextureRGB) {
   SetUpContexts();
   gl1_.MakeCurrent();

   GLuint tex1;
   glGenTextures(1, &tex1);

   glBindTexture(GL_TEXTURE_2D, tex1);
   uint32_t source_pixel = 0xFF000000;
   glTexImage2D(GL_TEXTURE_2D,
                0,
                GL_RGB,
                1, 1,
                0,
                GL_RGB,
                GL_UNSIGNED_BYTE,
                &source_pixel);

   GLbyte mailbox1[GL_MAILBOX_SIZE_CHROMIUM];
   glProduceTextureDirectCHROMIUM(tex1, mailbox1);
   glFlush();

   gl2_.MakeCurrent();

   GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox1);
   glBindTexture(GL_TEXTURE_2D, tex2);
   EXPECT_EQ(source_pixel, ReadTexel(tex2, 0, 0));

   GLbyte mailbox2[GL_MAILBOX_SIZE_CHROMIUM];
   glProduceTextureDirectCHROMIUM(tex2, mailbox2);
   glFlush();

   gl1_.MakeCurrent();

   tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox2);
   glBindTexture(GL_TEXTURE_2D, tex1);
   EXPECT_EQ(source_pixel, ReadTexel(tex1, 0, 0));
 }

 TEST_F(GLTextureMailboxTest, SharedTextures) {
   SetUpContexts();
   gl1_.MakeCurrent();
   GLuint tex1;
   glGenTextures(1, &tex1);

   glBindTexture(GL_TEXTURE_2D, tex1);
   uint32_t source_pixel = 0xFF0000FF;
   glTexImage2D(GL_TEXTURE_2D,
                0,
                GL_RGBA,
                1, 1,
                0,
                GL_RGBA,
                GL_UNSIGNED_BYTE,
                &source_pixel);
   GLbyte mailbox[GL_MAILBOX_SIZE_CHROMIUM];
   glProduceTextureDirectCHROMIUM(tex1, mailbox);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   glFlush();

   gl2_.MakeCurrent();
   GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox);
   glBindTexture(GL_TEXTURE_2D, tex2);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   // Change texture in context 2.
   source_pixel = 0xFF00FF00;
   glTexSubImage2D(GL_TEXTURE_2D,
                   0,
                   0, 0,
                   1, 1,
                   GL_RGBA,
                   GL_UNSIGNED_BYTE,
                   &source_pixel);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   glFlush();

   // Check it in context 1.
   gl1_.MakeCurrent();
   EXPECT_EQ(source_pixel, ReadTexel(tex1, 0, 0));
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   // Change parameters (note: ReadTexel will reset those).
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
                   GL_LINEAR_MIPMAP_NEAREST);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   glFlush();

   // Check in context 2.
   gl2_.MakeCurrent();
   GLint parameter = 0;
   glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, &parameter);
   EXPECT_EQ(GL_REPEAT, parameter);
   parameter = 0;
   glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, &parameter);
   EXPECT_EQ(GL_LINEAR, parameter);
   parameter = 0;
   glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, &parameter);
   EXPECT_EQ(GL_LINEAR_MIPMAP_NEAREST, parameter);

   // Delete texture in context 1.
   gl1_.MakeCurrent();
   glDeleteTextures(1, &tex1);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   // Check texture still exists in context 2.
   gl2_.MakeCurrent();
   EXPECT_EQ(source_pixel, ReadTexel(tex2, 0, 0));
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   // The mailbox should still exist too.
   GLuint tex3 = glCreateAndConsumeTextureCHROMIUM(mailbox);
   glBindTexture(GL_TEXTURE_2D, tex3);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   // Delete both textures.
   glDeleteTextures(1, &tex2);
   glDeleteTextures(1, &tex3);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   // Mailbox should be gone now.
   tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox);
   glBindTexture(GL_TEXTURE_2D, tex2);
   EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
   glDeleteTextures(1, &tex2);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
 }

 TEST_F(GLTextureMailboxTest, OrderingBarrierImpliesFlush) {
   SetUpContexts();
   gl2_.MakeCurrent();

   // If the current platform requires the use of virtualized GL contexts
   // for correctness, this harness does not respect that flag, so skip
   // this test.
   if (gl2_.workarounds().use_virtualized_gl_contexts) {
     SUCCEED() << "Platform requires virtualized GL contexts; skipping.";
     return;
   }

   GLuint fbo2 = 0;
   glGenFramebuffers(1, &fbo2);
   glBindFramebuffer(GL_FRAMEBUFFER, fbo2);
   gl1_.MakeCurrent();
   GLuint tex1 = 0;
   GLuint fbo1 = 0;
   AllocateTextureBackedFramebuffer(&tex1, &fbo1);

   // Many times:
   //  - Set the texture to one color in context 1
   //  - Mailbox the texture to context 2
   //  - Set the texture to another color in context 2
   //  - Mailbox the texture to context 1
   //  - Read back the framebuffer in context 1
   //  - Assert it's the color set by context 2

   GLbyte mailbox[GL_MAILBOX_SIZE_CHROMIUM];
   glProduceTextureDirectCHROMIUM(tex1, mailbox);

   for (int i = 0; i < 1000; ++i) {
     // Assume context 1 is current.
     // Clear to red
     glClearColor(1.0, 0.0, 0.0, 1.0);
     glClear(GL_COLOR_BUFFER_BIT);
     // Enforce ordering with respect to context 2.
     gl1_.gles2_implementation()->OrderingBarrierCHROMIUM();
     // Consume texture in context 2.
     gl2_.MakeCurrent();
     GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox);
     EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
     // Set up framebuffer in context 2 (strictly, not necessary, could
     // do this just once).
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                            tex2, 0);
     EXPECT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
               glCheckFramebufferStatus(GL_FRAMEBUFFER));
     // Clear to green.
     glClearColor(0.0, 1.0, 0.0, 1.0);
     glClear(GL_COLOR_BUFFER_BIT);
     glDeleteTextures(1, &tex2);
     // Enforce ordering with respect to context 2.
     gl2_.gles2_implementation()->OrderingBarrierCHROMIUM();
     // Consume texture in context 1.
     gl1_.MakeCurrent();
     // Read back framebuffer.
     GLubyte pixel[4];
     glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixel[0]);
     EXPECT_EQ(0, pixel[0]);
     EXPECT_EQ(255, pixel[1]);
     EXPECT_EQ(0, pixel[2]);
     EXPECT_EQ(255, pixel[3]);
   }

   glBindFramebuffer(GL_FRAMEBUFFER, 0);
   glDeleteFramebuffers(1, &fbo1);
   glBindTexture(GL_TEXTURE_2D, 0);
   glDeleteTextures(1, &tex1);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   gl2_.MakeCurrent();
   glBindFramebuffer(GL_FRAMEBUFFER, 0);
   glDeleteFramebuffers(1, &fbo2);
   glBindTexture(GL_TEXTURE_2D, 0);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
 }

 TEST_F(GLTextureMailboxTest, TakeFrontBuffer) {
   SetUpContexts();

   gl2_.MakeCurrent();
   glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
   glClearColor(0, 1, 1, 1);
   glClear(GL_COLOR_BUFFER_BIT);
   ::gles2::GetGLContext()->SwapBuffers(1);
   Mailbox mailbox = Mailbox::Generate();
   gl2_.decoder()->TakeFrontBuffer(mailbox);

   gl1_.MakeCurrent();
   GLuint tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
   glBindTexture(GL_TEXTURE_2D, tex1);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   EXPECT_EQ(0xFFFFFF00u, ReadTexel(tex1, 0, 0));

   gl2_.MakeCurrent();
   glClearColor(1, 0, 0, 1);
   glClear(GL_COLOR_BUFFER_BIT);
   ::gles2::GetGLContext()->SwapBuffers(1);

   gl1_.MakeCurrent();
   EXPECT_EQ(0xFFFFFF00u, ReadTexel(tex1, 0, 0));

   glDeleteTextures(1, &tex1);

   gl2_.MakeCurrent();
   gl2_.decoder()->ReturnFrontBuffer(mailbox, false);

   // Flushing doesn't matter, only SwapBuffers(1).
   glClearColor(0, 1, 0, 1);
   glClear(GL_COLOR_BUFFER_BIT);
   glFlush();

   Mailbox mailbox2 = Mailbox::Generate();
   gl2_.decoder()->TakeFrontBuffer(mailbox2);

   gl1_.MakeCurrent();
   tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox2.name);
   glBindTexture(GL_TEXTURE_2D, tex1);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   EXPECT_EQ(0xFF0000FFu, ReadTexel(tex1, 0, 0));

   gl2_.MakeCurrent();
   gl2_.Destroy();

   gl1_.MakeCurrent();
   EXPECT_EQ(0xFF0000FFu, ReadTexel(tex1, 0, 0));
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   glDeleteTextures(1, &tex1);
 }

 // The client, represented by |gl2_|, will request 5 frontbuffers, and then
 // start returning them.
 TEST_F(GLTextureMailboxTest, FrontBufferCache) {
   SetUpContexts();
   gl1_.MakeCurrent();

   std::vector<Mailbox> mailboxes;
   for (int i = 0; i < 5; ++i) {
     Mailbox mailbox = TakeAndConsumeMailbox();
     mailboxes.push_back(mailbox);
   }
   EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());
   EXPECT_EQ(5u, gl1_.decoder()->GetCreatedBackTextureCountForTest());

   // If the textures aren't lost, they're reused.
   for (int i = 0; i < 100; ++i) {
     gl1_.decoder()->ReturnFrontBuffer(mailboxes[0], false);
     mailboxes.erase(mailboxes.begin());

     Mailbox mailbox = TakeAndConsumeMailbox();
     mailboxes.push_back(mailbox);
   }

   EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());
   EXPECT_EQ(5u, gl1_.decoder()->GetCreatedBackTextureCountForTest());

   // If the textures are lost, they're not reused.
   for (int i = 0; i < 100; ++i) {
     gl1_.decoder()->ReturnFrontBuffer(mailboxes[0], true);
     mailboxes.erase(mailboxes.begin());

     Mailbox mailbox = TakeAndConsumeMailbox();
     mailboxes.push_back(mailbox);
   }

   EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());
   EXPECT_EQ(105u, gl1_.decoder()->GetCreatedBackTextureCountForTest());
 }

 // The client, represented by |gl2_|, will request and return 5 frontbuffers.
 // Then the size of the buffer will be changed. All cached frontbuffers should
 // be discarded.
 TEST_F(GLTextureMailboxTest, FrontBufferChangeSize) {
   SetUpContexts();
   gl1_.MakeCurrent();

   std::vector<Mailbox> mailboxes;
   for (int i = 0; i < 5; ++i) {
     Mailbox mailbox = TakeAndConsumeMailbox();
     mailboxes.push_back(mailbox);
   }
   EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());

   for (int i = 0; i < 5; ++i) {
     gl1_.decoder()->ReturnFrontBuffer(mailboxes[i], false);
   }
   mailboxes.clear();
   EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());

   glResizeCHROMIUM(21, 31, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
   ::gles2::GetGLContext()->SwapBuffers(1);
   EXPECT_EQ(0u, gl1_.decoder()->GetSavedBackTextureCountForTest());
 }

 // The client, represented by |gl2_|, will request and return 5 frontbuffers.
 // Then |gl1_| will start drawing with a different color. The returned
 // frontbuffers should pick up the new color.
 TEST_F(GLTextureMailboxTest, FrontBufferChangeColor) {
   GLManager::Options options1;
   options1.multisampled = true;
   gl1_.Initialize(options1);

   GLManager::Options options2;
   options2.share_mailbox_manager = &gl1_;
   gl2_.Initialize(options2);

   gl1_.MakeCurrent();
   std::vector<Mailbox> mailboxes;
   for (int i = 0; i < 5; ++i) {
     Mailbox mailbox = TakeAndConsumeMailbox();
     mailboxes.push_back(mailbox);
   }

   for (int i = 0; i < 5; ++i) {
     gl1_.decoder()->ReturnFrontBuffer(mailboxes[i], false);
   }
   mailboxes.clear();

   for (int i = 0; i < 5; ++i) {
     glClearColor(1, 0, 0, 1);
     glClear(GL_COLOR_BUFFER_BIT);
     ::gles2::GetGLContext()->SwapBuffers(1);

     Mailbox mailbox = Mailbox::Generate();
     gl1_.decoder()->TakeFrontBuffer(mailbox);

     // Normally, consumers of TakeFrontBuffer() must supply their own
     // synchronization mechanism. For this test, just use a glFinish().
     glFinish();

     gl2_.MakeCurrent();
     GLuint tex = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
     glBindTexture(GL_TEXTURE_2D, tex);

     EXPECT_EQ(0xFF0000FFu, ReadTexel(tex, 0, 0));

     glDeleteTextures(1, &tex);
     glFlush();
     gl1_.MakeCurrent();
   }
 }

 // Verify that front buffer textures have sampler parameters that will not cause
 // them to be incomplete when sampled
 TEST_F(GLTextureMailboxTest, FrontBufferSamplerParameters) {
   SetUpContexts();

   gl2_.MakeCurrent();
   glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
   glClearColor(0, 1, 1, 1);
   glClear(GL_COLOR_BUFFER_BIT);
   ::gles2::GetGLContext()->SwapBuffers(1);
   Mailbox mailbox = Mailbox::Generate();
   gl2_.decoder()->TakeFrontBuffer(mailbox);

   gl1_.MakeCurrent();
   GLuint tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
   glBindTexture(GL_TEXTURE_2D, tex1);
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

   constexpr std::pair<GLenum, GLint> expected_parameters[] = {
       {GL_TEXTURE_MAG_FILTER, GL_LINEAR},
       {GL_TEXTURE_MIN_FILTER, GL_LINEAR},
       {GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE},
       {GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE},
   };
   for (const auto& expected_parameter : expected_parameters) {
     GLint value = 0;
     glGetTexParameteriv(GL_TEXTURE_2D, expected_parameter.first, &value);
     EXPECT_EQ(expected_parameter.second, value);
   }
 }

 // http://crbug.com/281565
 #if !defined(OS_ANDROID)
 TEST_F(GLTextureMailboxTest, TakeFrontBufferMultipleContexts) {
   SetUpContexts();
   Mailbox mailbox[2];
   GLuint tex[2];

   GLManager::Options options;
   options.share_mailbox_manager = &gl1_;
   GLManager other_gl[2];
   for (size_t i = 0; i < 2; ++i) {
     other_gl[i].Initialize(options);
     other_gl[i].MakeCurrent();
     glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
     glClearColor(1 - i % 2, i % 2, 0, 1);
     glClear(GL_COLOR_BUFFER_BIT);
     ::gles2::GetGLContext()->SwapBuffers(0, 1);
     mailbox[i] = Mailbox::Generate();
     other_gl[i].decoder()->TakeFrontBuffer(mailbox[i]);
     // Make sure both "other gl" are in the same share group.
     if (!options.share_group_manager)
       options.share_group_manager = other_gl+i;
   }

   gl1_.MakeCurrent();
   for (size_t i = 0; i < 2; ++i) {
     tex[i] = glCreateAndConsumeTextureCHROMIUM(mailbox[i].name);
     glBindTexture(GL_TEXTURE_2D, tex[i]);
     EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
   }

   gl1_.MakeCurrent();
   EXPECT_EQ(0xFF0000FFu, ReadTexel(tex[0], 0, 0));
   EXPECT_EQ(0xFF00FF00u, ReadTexel(tex[1], 9, 9));

   for (size_t i = 0; i < 2; ++i) {
     other_gl[i].MakeCurrent();
     other_gl[i].Destroy();
   }

   gl1_.MakeCurrent();
   glDeleteTextures(2, tex);
 }
 #endif

 }  // namespace gpu
	// Copyright 2014 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 <GLES2/gl2.h>
	#include <GLES2/gl2ext.h>
	#include <GLES2/gl2extchromium.h>
	#include <stddef.h>
	#include <stdint.h>

	#include "gpu/command_buffer/client/gles2_implementation.h"
	#include "gpu/command_buffer/client/gles2_lib.h"
	#include "gpu/command_buffer/common/mailbox.h"
	#include "gpu/command_buffer/service/gles2_cmd_decoder.h"
	#include "gpu/command_buffer/service/mailbox_manager.h"
	#include "gpu/command_buffer/tests/gl_manager.h"
	#include "testing/gmock/include/gmock/gmock.h"
	#include "testing/gtest/include/gtest/gtest.h"
	#include "ui/gl/gl_share_group.h"

	namespace gpu {

	namespace {
	uint32_t ReadTexel(GLuint id, GLint x, GLint y) {
	GLint old_fbo = 0;
	glGetIntegerv(GL_FRAMEBUFFER_BINDING, &old_fbo);

	GLuint fbo;
	glGenFramebuffers(1, &fbo);
	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
	glFramebufferTexture2D(GL_FRAMEBUFFER,
	GL_COLOR_ATTACHMENT0,
	GL_TEXTURE_2D,
	id,
	0);
	// Some drivers (NVidia/SGX) require texture settings to be a certain way or
	// they won't report FRAMEBUFFER_COMPLETE.
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	EXPECT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
	glCheckFramebufferStatus(GL_FRAMEBUFFER));

	uint32_t texel = 0;
	glReadPixels(x, y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &texel);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	glBindFramebuffer(GL_FRAMEBUFFER, old_fbo);

	glDeleteFramebuffers(1, &fbo);

	return texel;
	}
	}

	class GLTextureMailboxTest : public testing::Test {
	protected:
	void SetUpContexts() {
	gl1_.Initialize(GLManager::Options());
	GLManager::Options options;
	options.share_mailbox_manager = &gl1_;
	gl2_.Initialize(options);
	}

	void TearDown() override {
	gl1_.Destroy();
	gl2_.Destroy();
	}

	// The second GL context takes and consumes a mailbox from the first GL
	// context. Assumes that \|gl1_\| is current.
	Mailbox TakeAndConsumeMailbox() {
	glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
	glClearColor(0, 1, 1, 1);
	glClear(GL_COLOR_BUFFER_BIT);
	::gles2::GetGLContext()->SwapBuffers(1);

	Mailbox mailbox = Mailbox::Generate();
	gl1_.decoder()->TakeFrontBuffer(mailbox);

	gl2_.MakeCurrent();
	GLuint tex = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
	glBindTexture(GL_TEXTURE_2D, tex);
	glDeleteTextures(1, &tex);
	glFlush();
	gl1_.MakeCurrent();
	return mailbox;
	}

	void AllocateTextureBackedFramebuffer(GLuint* tex, GLuint* fbo) {
	glGenTextures(1, tex);
	glBindTexture(GL_TEXTURE_2D, *tex);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE,
	nullptr);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glGenFramebuffers(1, fbo);
	glBindFramebuffer(GL_FRAMEBUFFER, *fbo);
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
	*tex, 0);
	ASSERT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
	glCheckFramebufferStatus(GL_FRAMEBUFFER));
	}

	GLManager gl1_;
	GLManager gl2_;
	};

	TEST_F(GLTextureMailboxTest, ProduceAndConsumeTexture) {
	SetUpContexts();
	gl1_.MakeCurrent();

	GLuint tex1;
	glGenTextures(1, &tex1);

	glBindTexture(GL_TEXTURE_2D, tex1);
	uint32_t source_pixel = 0xFF0000FF;
	glTexImage2D(GL_TEXTURE_2D,
	0,
	GL_RGBA,
	1, 1,
	0,
	GL_RGBA,
	GL_UNSIGNED_BYTE,
	&source_pixel);

	GLbyte mailbox1[GL_MAILBOX_SIZE_CHROMIUM];
	glProduceTextureDirectCHROMIUM(tex1, mailbox1);
	glFlush();

	gl2_.MakeCurrent();

	GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox1);
	glBindTexture(GL_TEXTURE_2D, tex2);
	EXPECT_EQ(source_pixel, ReadTexel(tex2, 0, 0));
	GLbyte mailbox2[GL_MAILBOX_SIZE_CHROMIUM];
	glProduceTextureDirectCHROMIUM(tex2, mailbox2);
	glFlush();

	gl1_.MakeCurrent();

	tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox2);
	glBindTexture(GL_TEXTURE_2D, tex1);
	EXPECT_EQ(source_pixel, ReadTexel(tex1, 0, 0));
	}

	TEST_F(GLTextureMailboxTest, ProduceAndConsumeTextureRGB) {
	SetUpContexts();
	gl1_.MakeCurrent();

	GLuint tex1;
	glGenTextures(1, &tex1);

	glBindTexture(GL_TEXTURE_2D, tex1);
	uint32_t source_pixel = 0xFF000000;
	glTexImage2D(GL_TEXTURE_2D,
	0,
	GL_RGB,
	1, 1,
	0,
	GL_RGB,
	GL_UNSIGNED_BYTE,
	&source_pixel);

	GLbyte mailbox1[GL_MAILBOX_SIZE_CHROMIUM];
	glProduceTextureDirectCHROMIUM(tex1, mailbox1);
	glFlush();

	gl2_.MakeCurrent();

	GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox1);
	glBindTexture(GL_TEXTURE_2D, tex2);
	EXPECT_EQ(source_pixel, ReadTexel(tex2, 0, 0));

	GLbyte mailbox2[GL_MAILBOX_SIZE_CHROMIUM];
	glProduceTextureDirectCHROMIUM(tex2, mailbox2);
	glFlush();

	gl1_.MakeCurrent();

	tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox2);
	glBindTexture(GL_TEXTURE_2D, tex1);
	EXPECT_EQ(source_pixel, ReadTexel(tex1, 0, 0));
	}

	TEST_F(GLTextureMailboxTest, SharedTextures) {
	SetUpContexts();
	gl1_.MakeCurrent();
	GLuint tex1;
	glGenTextures(1, &tex1);

	glBindTexture(GL_TEXTURE_2D, tex1);
	uint32_t source_pixel = 0xFF0000FF;
	glTexImage2D(GL_TEXTURE_2D,
	0,
	GL_RGBA,
	1, 1,
	0,
	GL_RGBA,
	GL_UNSIGNED_BYTE,
	&source_pixel);
	GLbyte mailbox[GL_MAILBOX_SIZE_CHROMIUM];
	glProduceTextureDirectCHROMIUM(tex1, mailbox);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	glFlush();

	gl2_.MakeCurrent();
	GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox);
	glBindTexture(GL_TEXTURE_2D, tex2);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	// Change texture in context 2.
	source_pixel = 0xFF00FF00;
	glTexSubImage2D(GL_TEXTURE_2D,
	0,
	0, 0,
	1, 1,
	GL_RGBA,
	GL_UNSIGNED_BYTE,
	&source_pixel);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	glFlush();

	// Check it in context 1.
	gl1_.MakeCurrent();
	EXPECT_EQ(source_pixel, ReadTexel(tex1, 0, 0));
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	// Change parameters (note: ReadTexel will reset those).
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
	GL_LINEAR_MIPMAP_NEAREST);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	glFlush();

	// Check in context 2.
	gl2_.MakeCurrent();
	GLint parameter = 0;
	glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, &parameter);
	EXPECT_EQ(GL_REPEAT, parameter);
	parameter = 0;
	glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, &parameter);
	EXPECT_EQ(GL_LINEAR, parameter);
	parameter = 0;
	glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, &parameter);
	EXPECT_EQ(GL_LINEAR_MIPMAP_NEAREST, parameter);

	// Delete texture in context 1.
	gl1_.MakeCurrent();
	glDeleteTextures(1, &tex1);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	// Check texture still exists in context 2.
	gl2_.MakeCurrent();
	EXPECT_EQ(source_pixel, ReadTexel(tex2, 0, 0));
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	// The mailbox should still exist too.
	GLuint tex3 = glCreateAndConsumeTextureCHROMIUM(mailbox);
	glBindTexture(GL_TEXTURE_2D, tex3);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	// Delete both textures.
	glDeleteTextures(1, &tex2);
	glDeleteTextures(1, &tex3);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	// Mailbox should be gone now.
	tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox);
	glBindTexture(GL_TEXTURE_2D, tex2);
	EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
	glDeleteTextures(1, &tex2);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	}

	TEST_F(GLTextureMailboxTest, OrderingBarrierImpliesFlush) {
	SetUpContexts();
	gl2_.MakeCurrent();

	// If the current platform requires the use of virtualized GL contexts
	// for correctness, this harness does not respect that flag, so skip
	// this test.
	if (gl2_.workarounds().use_virtualized_gl_contexts) {
	SUCCEED() << "Platform requires virtualized GL contexts; skipping.";
	return;
	}

	GLuint fbo2 = 0;
	glGenFramebuffers(1, &fbo2);
	glBindFramebuffer(GL_FRAMEBUFFER, fbo2);
	gl1_.MakeCurrent();
	GLuint tex1 = 0;
	GLuint fbo1 = 0;
	AllocateTextureBackedFramebuffer(&tex1, &fbo1);

	// Many times:
	// - Set the texture to one color in context 1
	// - Mailbox the texture to context 2
	// - Set the texture to another color in context 2
	// - Mailbox the texture to context 1
	// - Read back the framebuffer in context 1
	// - Assert it's the color set by context 2

	GLbyte mailbox[GL_MAILBOX_SIZE_CHROMIUM];
	glProduceTextureDirectCHROMIUM(tex1, mailbox);

	for (int i = 0; i < 1000; ++i) {
	// Assume context 1 is current.
	// Clear to red
	glClearColor(1.0, 0.0, 0.0, 1.0);
	glClear(GL_COLOR_BUFFER_BIT);
	// Enforce ordering with respect to context 2.
	gl1_.gles2_implementation()->OrderingBarrierCHROMIUM();
	// Consume texture in context 2.
	gl2_.MakeCurrent();
	GLuint tex2 = glCreateAndConsumeTextureCHROMIUM(mailbox);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	// Set up framebuffer in context 2 (strictly, not necessary, could
	// do this just once).
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
	tex2, 0);
	EXPECT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
	glCheckFramebufferStatus(GL_FRAMEBUFFER));
	// Clear to green.
	glClearColor(0.0, 1.0, 0.0, 1.0);
	glClear(GL_COLOR_BUFFER_BIT);
	glDeleteTextures(1, &tex2);
	// Enforce ordering with respect to context 2.
	gl2_.gles2_implementation()->OrderingBarrierCHROMIUM();
	// Consume texture in context 1.
	gl1_.MakeCurrent();
	// Read back framebuffer.
	GLubyte pixel[4];
	glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixel[0]);
	EXPECT_EQ(0, pixel[0]);
	EXPECT_EQ(255, pixel[1]);
	EXPECT_EQ(0, pixel[2]);
	EXPECT_EQ(255, pixel[3]);
	}

	glBindFramebuffer(GL_FRAMEBUFFER, 0);
	glDeleteFramebuffers(1, &fbo1);
	glBindTexture(GL_TEXTURE_2D, 0);
	glDeleteTextures(1, &tex1);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	gl2_.MakeCurrent();
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
	glDeleteFramebuffers(1, &fbo2);
	glBindTexture(GL_TEXTURE_2D, 0);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	}

	TEST_F(GLTextureMailboxTest, TakeFrontBuffer) {
	SetUpContexts();

	gl2_.MakeCurrent();
	glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
	glClearColor(0, 1, 1, 1);
	glClear(GL_COLOR_BUFFER_BIT);
	::gles2::GetGLContext()->SwapBuffers(1);
	Mailbox mailbox = Mailbox::Generate();
	gl2_.decoder()->TakeFrontBuffer(mailbox);

	gl1_.MakeCurrent();
	GLuint tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
	glBindTexture(GL_TEXTURE_2D, tex1);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	EXPECT_EQ(0xFFFFFF00u, ReadTexel(tex1, 0, 0));

	gl2_.MakeCurrent();
	glClearColor(1, 0, 0, 1);
	glClear(GL_COLOR_BUFFER_BIT);
	::gles2::GetGLContext()->SwapBuffers(1);

	gl1_.MakeCurrent();
	EXPECT_EQ(0xFFFFFF00u, ReadTexel(tex1, 0, 0));

	glDeleteTextures(1, &tex1);

	gl2_.MakeCurrent();
	gl2_.decoder()->ReturnFrontBuffer(mailbox, false);

	// Flushing doesn't matter, only SwapBuffers(1).
	glClearColor(0, 1, 0, 1);
	glClear(GL_COLOR_BUFFER_BIT);
	glFlush();

	Mailbox mailbox2 = Mailbox::Generate();
	gl2_.decoder()->TakeFrontBuffer(mailbox2);

	gl1_.MakeCurrent();
	tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox2.name);
	glBindTexture(GL_TEXTURE_2D, tex1);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	EXPECT_EQ(0xFF0000FFu, ReadTexel(tex1, 0, 0));

	gl2_.MakeCurrent();
	gl2_.Destroy();

	gl1_.MakeCurrent();
	EXPECT_EQ(0xFF0000FFu, ReadTexel(tex1, 0, 0));
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	glDeleteTextures(1, &tex1);
	}

	// The client, represented by \|gl2_\|, will request 5 frontbuffers, and then
	// start returning them.
	TEST_F(GLTextureMailboxTest, FrontBufferCache) {
	SetUpContexts();
	gl1_.MakeCurrent();

	std::vector<Mailbox> mailboxes;
	for (int i = 0; i < 5; ++i) {
	Mailbox mailbox = TakeAndConsumeMailbox();
	mailboxes.push_back(mailbox);
	}
	EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());
	EXPECT_EQ(5u, gl1_.decoder()->GetCreatedBackTextureCountForTest());

	// If the textures aren't lost, they're reused.
	for (int i = 0; i < 100; ++i) {
	gl1_.decoder()->ReturnFrontBuffer(mailboxes[0], false);
	mailboxes.erase(mailboxes.begin());

	Mailbox mailbox = TakeAndConsumeMailbox();
	mailboxes.push_back(mailbox);
	}

	EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());
	EXPECT_EQ(5u, gl1_.decoder()->GetCreatedBackTextureCountForTest());

	// If the textures are lost, they're not reused.
	for (int i = 0; i < 100; ++i) {
	gl1_.decoder()->ReturnFrontBuffer(mailboxes[0], true);
	mailboxes.erase(mailboxes.begin());

	Mailbox mailbox = TakeAndConsumeMailbox();
	mailboxes.push_back(mailbox);
	}

	EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());
	EXPECT_EQ(105u, gl1_.decoder()->GetCreatedBackTextureCountForTest());
	}

	// The client, represented by \|gl2_\|, will request and return 5 frontbuffers.
	// Then the size of the buffer will be changed. All cached frontbuffers should
	// be discarded.
	TEST_F(GLTextureMailboxTest, FrontBufferChangeSize) {
	SetUpContexts();
	gl1_.MakeCurrent();

	std::vector<Mailbox> mailboxes;
	for (int i = 0; i < 5; ++i) {
	Mailbox mailbox = TakeAndConsumeMailbox();
	mailboxes.push_back(mailbox);
	}
	EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());

	for (int i = 0; i < 5; ++i) {
	gl1_.decoder()->ReturnFrontBuffer(mailboxes[i], false);
	}
	mailboxes.clear();
	EXPECT_EQ(5u, gl1_.decoder()->GetSavedBackTextureCountForTest());

	glResizeCHROMIUM(21, 31, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
	::gles2::GetGLContext()->SwapBuffers(1);
	EXPECT_EQ(0u, gl1_.decoder()->GetSavedBackTextureCountForTest());
	}

	// The client, represented by \|gl2_\|, will request and return 5 frontbuffers.
	// Then \|gl1_\| will start drawing with a different color. The returned
	// frontbuffers should pick up the new color.
	TEST_F(GLTextureMailboxTest, FrontBufferChangeColor) {
	GLManager::Options options1;
	options1.multisampled = true;
	gl1_.Initialize(options1);

	GLManager::Options options2;
	options2.share_mailbox_manager = &gl1_;
	gl2_.Initialize(options2);

	gl1_.MakeCurrent();
	std::vector<Mailbox> mailboxes;
	for (int i = 0; i < 5; ++i) {
	Mailbox mailbox = TakeAndConsumeMailbox();
	mailboxes.push_back(mailbox);
	}

	for (int i = 0; i < 5; ++i) {
	gl1_.decoder()->ReturnFrontBuffer(mailboxes[i], false);
	}
	mailboxes.clear();

	for (int i = 0; i < 5; ++i) {
	glClearColor(1, 0, 0, 1);
	glClear(GL_COLOR_BUFFER_BIT);
	::gles2::GetGLContext()->SwapBuffers(1);

	Mailbox mailbox = Mailbox::Generate();
	gl1_.decoder()->TakeFrontBuffer(mailbox);

	// Normally, consumers of TakeFrontBuffer() must supply their own
	// synchronization mechanism. For this test, just use a glFinish().
	glFinish();

	gl2_.MakeCurrent();
	GLuint tex = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
	glBindTexture(GL_TEXTURE_2D, tex);

	EXPECT_EQ(0xFF0000FFu, ReadTexel(tex, 0, 0));

	glDeleteTextures(1, &tex);
	glFlush();
	gl1_.MakeCurrent();
	}
	}

	// Verify that front buffer textures have sampler parameters that will not cause
	// them to be incomplete when sampled
	TEST_F(GLTextureMailboxTest, FrontBufferSamplerParameters) {
	SetUpContexts();

	gl2_.MakeCurrent();
	glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
	glClearColor(0, 1, 1, 1);
	glClear(GL_COLOR_BUFFER_BIT);
	::gles2::GetGLContext()->SwapBuffers(1);
	Mailbox mailbox = Mailbox::Generate();
	gl2_.decoder()->TakeFrontBuffer(mailbox);

	gl1_.MakeCurrent();
	GLuint tex1 = glCreateAndConsumeTextureCHROMIUM(mailbox.name);
	glBindTexture(GL_TEXTURE_2D, tex1);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());

	constexpr std::pair<GLenum, GLint> expected_parameters[] = {
	{GL_TEXTURE_MAG_FILTER, GL_LINEAR},
	{GL_TEXTURE_MIN_FILTER, GL_LINEAR},
	{GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE},
	{GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE},
	};
	for (const auto& expected_parameter : expected_parameters) {
	GLint value = 0;
	glGetTexParameteriv(GL_TEXTURE_2D, expected_parameter.first, &value);
	EXPECT_EQ(expected_parameter.second, value);
	}
	}

	// http://crbug.com/281565
	#if !defined(OS_ANDROID)
	TEST_F(GLTextureMailboxTest, TakeFrontBufferMultipleContexts) {
	SetUpContexts();
	Mailbox mailbox[2];
	GLuint tex[2];

	GLManager::Options options;
	options.share_mailbox_manager = &gl1_;
	GLManager other_gl[2];
	for (size_t i = 0; i < 2; ++i) {
	other_gl[i].Initialize(options);
	other_gl[i].MakeCurrent();
	glResizeCHROMIUM(10, 10, 1, GL_COLOR_SPACE_UNSPECIFIED_CHROMIUM, true);
	glClearColor(1 - i % 2, i % 2, 0, 1);
	glClear(GL_COLOR_BUFFER_BIT);
	::gles2::GetGLContext()->SwapBuffers(0, 1);
	mailbox[i] = Mailbox::Generate();
	other_gl[i].decoder()->TakeFrontBuffer(mailbox[i]);
	// Make sure both "other gl" are in the same share group.
	if (!options.share_group_manager)
	options.share_group_manager = other_gl+i;
	}

	gl1_.MakeCurrent();
	for (size_t i = 0; i < 2; ++i) {
	tex[i] = glCreateAndConsumeTextureCHROMIUM(mailbox[i].name);
	glBindTexture(GL_TEXTURE_2D, tex[i]);
	EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
	}

	gl1_.MakeCurrent();
	EXPECT_EQ(0xFF0000FFu, ReadTexel(tex[0], 0, 0));
	EXPECT_EQ(0xFF00FF00u, ReadTexel(tex[1], 9, 9));

	for (size_t i = 0; i < 2; ++i) {
	other_gl[i].MakeCurrent();
	other_gl[i].Destroy();
	}

	gl1_.MakeCurrent();
	glDeleteTextures(2, tex);
	}
	#endif

	} // namespace gpu