cc/raster/one_copy_raster_buffer_provider.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 "cc/raster/one_copy_raster_buffer_provider.h"

 #include <stdint.h>

 #include <algorithm>
 #include <limits>
 #include <utility>

 #include "base/macros.h"
 #include "cc/base/math_util.h"
 #include "cc/raster/staging_buffer_pool.h"
 #include "cc/resources/platform_color.h"
 #include "cc/resources/resource_format.h"
 #include "cc/resources/resource_util.h"
 #include "cc/resources/scoped_resource.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "gpu/command_buffer/client/gpu_memory_buffer_manager.h"
 #include "ui/gfx/buffer_format_util.h"

 namespace cc {
 namespace {

 class RasterBufferImpl : public RasterBuffer {
  public:
   RasterBufferImpl(OneCopyRasterBufferProvider* worker_pool,
                    ResourceProvider* resource_provider,
                    ResourceFormat resource_format,
                    const Resource* resource,
                    uint64_t previous_content_id)
       : worker_pool_(worker_pool),
         resource_(resource),
         lock_(resource_provider, resource->id()),
         previous_content_id_(previous_content_id) {}

   ~RasterBufferImpl() override {}

   // Overridden from RasterBuffer:
   void Playback(
       const RasterSource* raster_source,
       const gfx::Rect& raster_full_rect,
       const gfx::Rect& raster_dirty_rect,
       uint64_t new_content_id,
       float scale,
       const RasterSource::PlaybackSettings& playback_settings) override {
     worker_pool_->PlaybackAndCopyOnWorkerThread(
         resource_, &lock_, raster_source, raster_full_rect, raster_dirty_rect,
         scale, playback_settings, previous_content_id_, new_content_id);
   }

  private:
   OneCopyRasterBufferProvider* worker_pool_;
   const Resource* resource_;
   ResourceProvider::ScopedWriteLockGL lock_;
   uint64_t previous_content_id_;

   DISALLOW_COPY_AND_ASSIGN(RasterBufferImpl);
 };

 // 4MiB is the size of 4 512x512 tiles, which has proven to be a good
 // default batch size for copy operations.
 const int kMaxBytesPerCopyOperation = 1024 * 1024 * 4;

 }  // namespace

 // static
 std::unique_ptr<RasterBufferProvider> OneCopyRasterBufferProvider::Create(
     base::SequencedTaskRunner* task_runner,
     ContextProvider* context_provider,
     ResourceProvider* resource_provider,
     int max_copy_texture_chromium_size,
     bool use_partial_raster,
     int max_staging_buffer_usage_in_bytes,
     ResourceFormat preferred_tile_format) {
   return base::WrapUnique<RasterBufferProvider>(new OneCopyRasterBufferProvider(
       task_runner, resource_provider, max_copy_texture_chromium_size,
       use_partial_raster, max_staging_buffer_usage_in_bytes,
       preferred_tile_format));
 }

 OneCopyRasterBufferProvider::OneCopyRasterBufferProvider(
     base::SequencedTaskRunner* task_runner,
     ResourceProvider* resource_provider,
     int max_copy_texture_chromium_size,
     bool use_partial_raster,
     int max_staging_buffer_usage_in_bytes,
     ResourceFormat preferred_tile_format)
     : resource_provider_(resource_provider),
       max_bytes_per_copy_operation_(
           max_copy_texture_chromium_size
               ? std::min(kMaxBytesPerCopyOperation,
                          max_copy_texture_chromium_size)
               : kMaxBytesPerCopyOperation),
       use_partial_raster_(use_partial_raster),
       bytes_scheduled_since_last_flush_(0),
       preferred_tile_format_(preferred_tile_format) {
   staging_pool_ = StagingBufferPool::Create(task_runner, resource_provider,
                                             use_partial_raster,
                                             max_staging_buffer_usage_in_bytes);
 }

 OneCopyRasterBufferProvider::~OneCopyRasterBufferProvider() {}

 std::unique_ptr<RasterBuffer>
 OneCopyRasterBufferProvider::AcquireBufferForRaster(
     const Resource* resource,
     uint64_t resource_content_id,
     uint64_t previous_content_id) {
   // TODO(danakj): If resource_content_id != 0, we only need to copy/upload
   // the dirty rect.
   return base::WrapUnique<RasterBuffer>(
       new RasterBufferImpl(this, resource_provider_, resource->format(),
                            resource, previous_content_id));
 }

 void OneCopyRasterBufferProvider::ReleaseBufferForRaster(
     std::unique_ptr<RasterBuffer> buffer) {
   // Nothing to do here. RasterBufferImpl destructor cleans up after itself.
 }

 void OneCopyRasterBufferProvider::OrderingBarrier() {
   TRACE_EVENT0("cc", "OneCopyRasterBufferProvider::OrderingBarrier");

   resource_provider_->output_surface()
       ->context_provider()
       ->ContextGL()
       ->OrderingBarrierCHROMIUM();
 }

 ResourceFormat OneCopyRasterBufferProvider::GetResourceFormat(
     bool must_support_alpha) const {
   if (resource_provider_->IsResourceFormatSupported(preferred_tile_format_) &&
       (DoesResourceFormatSupportAlpha(preferred_tile_format_) ||
        !must_support_alpha)) {
     return preferred_tile_format_;
   }

   return resource_provider_->best_texture_format();
 }

 bool OneCopyRasterBufferProvider::GetResourceRequiresSwizzle(
     bool must_support_alpha) const {
   return ResourceFormatRequiresSwizzle(GetResourceFormat(must_support_alpha));
 }

 void OneCopyRasterBufferProvider::Shutdown() {
   staging_pool_->Shutdown();
 }

 void OneCopyRasterBufferProvider::PlaybackAndCopyOnWorkerThread(
     const Resource* resource,
     ResourceProvider::ScopedWriteLockGL* resource_lock,
     const RasterSource* raster_source,
     const gfx::Rect& raster_full_rect,
     const gfx::Rect& raster_dirty_rect,
     float scale,
     const RasterSource::PlaybackSettings& playback_settings,
     uint64_t previous_content_id,
     uint64_t new_content_id) {
   std::unique_ptr<StagingBuffer> staging_buffer =
       staging_pool_->AcquireStagingBuffer(resource, previous_content_id);

   PlaybackToStagingBuffer(staging_buffer.get(), resource, raster_source,
                           raster_full_rect, raster_dirty_rect, scale,
                           playback_settings, previous_content_id,
                           new_content_id);

   CopyOnWorkerThread(staging_buffer.get(), resource, resource_lock,
                      raster_source, previous_content_id, new_content_id);

   staging_pool_->ReleaseStagingBuffer(std::move(staging_buffer));
 }

 void OneCopyRasterBufferProvider::PlaybackToStagingBuffer(
     StagingBuffer* staging_buffer,
     const Resource* resource,
     const RasterSource* raster_source,
     const gfx::Rect& raster_full_rect,
     const gfx::Rect& raster_dirty_rect,
     float scale,
     const RasterSource::PlaybackSettings& playback_settings,
     uint64_t previous_content_id,
     uint64_t new_content_id) {
   // Allocate GpuMemoryBuffer if necessary. If using partial raster, we
   // must allocate a buffer with BufferUsage CPU_READ_WRITE_PERSISTENT.
   if (!staging_buffer->gpu_memory_buffer) {
     staging_buffer->gpu_memory_buffer =
         resource_provider_->gpu_memory_buffer_manager()
             ->AllocateGpuMemoryBuffer(
                 staging_buffer->size, BufferFormat(resource->format()),
                 use_partial_raster_
                     ? gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT
                     : gfx::BufferUsage::GPU_READ_CPU_READ_WRITE,
                 gpu::kNullSurfaceHandle);
   }

   gfx::Rect playback_rect = raster_full_rect;
   if (use_partial_raster_ && previous_content_id) {
     // Reduce playback rect to dirty region if the content id of the staging
     // buffer matches the prevous content id.
     if (previous_content_id == staging_buffer->content_id)
       playback_rect.Intersect(raster_dirty_rect);
   }

   if (staging_buffer->gpu_memory_buffer) {
     gfx::GpuMemoryBuffer* buffer = staging_buffer->gpu_memory_buffer.get();
     DCHECK_EQ(1u, gfx::NumberOfPlanesForBufferFormat(buffer->GetFormat()));
     bool rv = buffer->Map();
     DCHECK(rv);
     DCHECK(buffer->memory(0));
     // RasterBufferProvider::PlaybackToMemory only supports unsigned strides.
     DCHECK_GE(buffer->stride(0), 0);

     DCHECK(!playback_rect.IsEmpty())
         << "Why are we rastering a tile that's not dirty?";
     RasterBufferProvider::PlaybackToMemory(
         buffer->memory(0), resource->format(), staging_buffer->size,
         buffer->stride(0), raster_source, raster_full_rect, playback_rect,
         scale, playback_settings);
     buffer->Unmap();
     staging_buffer->content_id = new_content_id;
   }
 }

 void OneCopyRasterBufferProvider::CopyOnWorkerThread(
     StagingBuffer* staging_buffer,
     const Resource* resource,
     ResourceProvider::ScopedWriteLockGL* resource_lock,
     const RasterSource* raster_source,
     uint64_t previous_content_id,
     uint64_t new_content_id) {
   ContextProvider* context_provider =
       resource_provider_->output_surface()->worker_context_provider();
   DCHECK(context_provider);

   {
     ContextProvider::ScopedContextLock scoped_context(context_provider);

     gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
     DCHECK(gl);

     unsigned image_target =
         resource_provider_->GetImageTextureTarget(resource->format());

     // Create and bind staging texture.
     if (!staging_buffer->texture_id) {
       gl->GenTextures(1, &staging_buffer->texture_id);
       gl->BindTexture(image_target, staging_buffer->texture_id);
       gl->TexParameteri(image_target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
       gl->TexParameteri(image_target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
       gl->TexParameteri(image_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
       gl->TexParameteri(image_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
     } else {
       gl->BindTexture(image_target, staging_buffer->texture_id);
     }

     // Create and bind image.
     if (!staging_buffer->image_id) {
       if (staging_buffer->gpu_memory_buffer) {
         staging_buffer->image_id = gl->CreateImageCHROMIUM(
             staging_buffer->gpu_memory_buffer->AsClientBuffer(),
             staging_buffer->size.width(), staging_buffer->size.height(),
             GLInternalFormat(resource->format()));
         gl->BindTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
       }
     } else {
       gl->ReleaseTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
       gl->BindTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
     }

     // Unbind staging texture.
     gl->BindTexture(image_target, 0);

     if (resource_provider_->use_sync_query()) {
       if (!staging_buffer->query_id)
         gl->GenQueriesEXT(1, &staging_buffer->query_id);

 #if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY)
       // TODO(reveman): This avoids a performance problem on ARM ChromeOS
       // devices. crbug.com/580166
       gl->BeginQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM, staging_buffer->query_id);
 #else
       gl->BeginQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM,
                         staging_buffer->query_id);
 #endif
     }

     // Since compressed texture's cannot be pre-allocated we might have an
     // unallocated resource in which case we need to perform a full size copy.
     if (IsResourceFormatCompressed(resource->format())) {
       gl->CompressedCopyTextureCHROMIUM(staging_buffer->texture_id,
                                         resource_lock->texture_id());
     } else {
       int bytes_per_row = ResourceUtil::UncheckedWidthInBytes<int>(
           resource->size().width(), resource->format());
       int chunk_size_in_rows =
           std::max(1, max_bytes_per_copy_operation_ / bytes_per_row);
       // Align chunk size to 4. Required to support compressed texture formats.
       chunk_size_in_rows = MathUtil::UncheckedRoundUp(chunk_size_in_rows, 4);
       int y = 0;
       int height = resource->size().height();
       while (y < height) {
         // Copy at most |chunk_size_in_rows|.
         int rows_to_copy = std::min(chunk_size_in_rows, height - y);
         DCHECK_GT(rows_to_copy, 0);

         gl->CopySubTextureCHROMIUM(
             staging_buffer->texture_id, resource_lock->texture_id(), 0, y, 0, y,
             resource->size().width(), rows_to_copy, false, false, false);
         y += rows_to_copy;

         // Increment |bytes_scheduled_since_last_flush_| by the amount of memory
         // used for this copy operation.
         bytes_scheduled_since_last_flush_ += rows_to_copy * bytes_per_row;

         if (bytes_scheduled_since_last_flush_ >=
             max_bytes_per_copy_operation_) {
           gl->ShallowFlushCHROMIUM();
           bytes_scheduled_since_last_flush_ = 0;
         }
       }
     }

     if (resource_provider_->use_sync_query()) {
 #if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY)
       gl->EndQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM);
 #else
       gl->EndQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM);
 #endif
     }

     const uint64_t fence_sync = gl->InsertFenceSyncCHROMIUM();

     // Barrier to sync worker context output to cc context.
     gl->OrderingBarrierCHROMIUM();

     // Generate sync token after the barrier for cross context synchronization.
     gpu::SyncToken sync_token;
     gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
     resource_lock->UpdateResourceSyncToken(sync_token);
   }
 }

 }  // namespace cc
	// 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 "cc/raster/one_copy_raster_buffer_provider.h"

	#include <stdint.h>

	#include <algorithm>
	#include <limits>
	#include <utility>

	#include "base/macros.h"
	#include "cc/base/math_util.h"
	#include "cc/raster/staging_buffer_pool.h"
	#include "cc/resources/platform_color.h"
	#include "cc/resources/resource_format.h"
	#include "cc/resources/resource_util.h"
	#include "cc/resources/scoped_resource.h"
	#include "gpu/GLES2/gl2extchromium.h"
	#include "gpu/command_buffer/client/gles2_interface.h"
	#include "gpu/command_buffer/client/gpu_memory_buffer_manager.h"
	#include "ui/gfx/buffer_format_util.h"

	namespace cc {
	namespace {

	class RasterBufferImpl : public RasterBuffer {
	public:
	RasterBufferImpl(OneCopyRasterBufferProvider* worker_pool,
	ResourceProvider* resource_provider,
	ResourceFormat resource_format,
	const Resource* resource,
	uint64_t previous_content_id)
	: worker_pool_(worker_pool),
	resource_(resource),
	lock_(resource_provider, resource->id()),
	previous_content_id_(previous_content_id) {}

	~RasterBufferImpl() override {}

	// Overridden from RasterBuffer:
	void Playback(
	const RasterSource* raster_source,
	const gfx::Rect& raster_full_rect,
	const gfx::Rect& raster_dirty_rect,
	uint64_t new_content_id,
	float scale,
	const RasterSource::PlaybackSettings& playback_settings) override {
	worker_pool_->PlaybackAndCopyOnWorkerThread(
	resource_, &lock_, raster_source, raster_full_rect, raster_dirty_rect,
	scale, playback_settings, previous_content_id_, new_content_id);
	}

	private:
	OneCopyRasterBufferProvider* worker_pool_;
	const Resource* resource_;
	ResourceProvider::ScopedWriteLockGL lock_;
	uint64_t previous_content_id_;

	DISALLOW_COPY_AND_ASSIGN(RasterBufferImpl);
	};

	// 4MiB is the size of 4 512x512 tiles, which has proven to be a good
	// default batch size for copy operations.
	const int kMaxBytesPerCopyOperation = 1024 * 1024 * 4;

	} // namespace

	// static
	std::unique_ptr<RasterBufferProvider> OneCopyRasterBufferProvider::Create(
	base::SequencedTaskRunner* task_runner,
	ContextProvider* context_provider,
	ResourceProvider* resource_provider,
	int max_copy_texture_chromium_size,
	bool use_partial_raster,
	int max_staging_buffer_usage_in_bytes,
	ResourceFormat preferred_tile_format) {
	return base::WrapUnique<RasterBufferProvider>(new OneCopyRasterBufferProvider(
	task_runner, resource_provider, max_copy_texture_chromium_size,
	use_partial_raster, max_staging_buffer_usage_in_bytes,
	preferred_tile_format));
	}

	OneCopyRasterBufferProvider::OneCopyRasterBufferProvider(
	base::SequencedTaskRunner* task_runner,
	ResourceProvider* resource_provider,
	int max_copy_texture_chromium_size,
	bool use_partial_raster,
	int max_staging_buffer_usage_in_bytes,
	ResourceFormat preferred_tile_format)
	: resource_provider_(resource_provider),
	max_bytes_per_copy_operation_(
	max_copy_texture_chromium_size
	? std::min(kMaxBytesPerCopyOperation,
	max_copy_texture_chromium_size)
	: kMaxBytesPerCopyOperation),
	use_partial_raster_(use_partial_raster),
	bytes_scheduled_since_last_flush_(0),
	preferred_tile_format_(preferred_tile_format) {
	staging_pool_ = StagingBufferPool::Create(task_runner, resource_provider,
	use_partial_raster,
	max_staging_buffer_usage_in_bytes);
	}

	OneCopyRasterBufferProvider::~OneCopyRasterBufferProvider() {}

	std::unique_ptr<RasterBuffer>
	OneCopyRasterBufferProvider::AcquireBufferForRaster(
	const Resource* resource,
	uint64_t resource_content_id,
	uint64_t previous_content_id) {
	// TODO(danakj): If resource_content_id != 0, we only need to copy/upload
	// the dirty rect.
	return base::WrapUnique<RasterBuffer>(
	new RasterBufferImpl(this, resource_provider_, resource->format(),
	resource, previous_content_id));
	}

	void OneCopyRasterBufferProvider::ReleaseBufferForRaster(
	std::unique_ptr<RasterBuffer> buffer) {
	// Nothing to do here. RasterBufferImpl destructor cleans up after itself.
	}

	void OneCopyRasterBufferProvider::OrderingBarrier() {
	TRACE_EVENT0("cc", "OneCopyRasterBufferProvider::OrderingBarrier");

	resource_provider_->output_surface()
	->context_provider()
	->ContextGL()
	->OrderingBarrierCHROMIUM();
	}

	ResourceFormat OneCopyRasterBufferProvider::GetResourceFormat(
	bool must_support_alpha) const {
	if (resource_provider_->IsResourceFormatSupported(preferred_tile_format_) &&
	(DoesResourceFormatSupportAlpha(preferred_tile_format_) \|\|
	!must_support_alpha)) {
	return preferred_tile_format_;
	}

	return resource_provider_->best_texture_format();
	}

	bool OneCopyRasterBufferProvider::GetResourceRequiresSwizzle(
	bool must_support_alpha) const {
	return ResourceFormatRequiresSwizzle(GetResourceFormat(must_support_alpha));
	}

	void OneCopyRasterBufferProvider::Shutdown() {
	staging_pool_->Shutdown();
	}

	void OneCopyRasterBufferProvider::PlaybackAndCopyOnWorkerThread(
	const Resource* resource,
	ResourceProvider::ScopedWriteLockGL* resource_lock,
	const RasterSource* raster_source,
	const gfx::Rect& raster_full_rect,
	const gfx::Rect& raster_dirty_rect,
	float scale,
	const RasterSource::PlaybackSettings& playback_settings,
	uint64_t previous_content_id,
	uint64_t new_content_id) {
	std::unique_ptr<StagingBuffer> staging_buffer =
	staging_pool_->AcquireStagingBuffer(resource, previous_content_id);

	PlaybackToStagingBuffer(staging_buffer.get(), resource, raster_source,
	raster_full_rect, raster_dirty_rect, scale,
	playback_settings, previous_content_id,
	new_content_id);

	CopyOnWorkerThread(staging_buffer.get(), resource, resource_lock,
	raster_source, previous_content_id, new_content_id);

	staging_pool_->ReleaseStagingBuffer(std::move(staging_buffer));
	}

	void OneCopyRasterBufferProvider::PlaybackToStagingBuffer(
	StagingBuffer* staging_buffer,
	const Resource* resource,
	const RasterSource* raster_source,
	const gfx::Rect& raster_full_rect,
	const gfx::Rect& raster_dirty_rect,
	float scale,
	const RasterSource::PlaybackSettings& playback_settings,
	uint64_t previous_content_id,
	uint64_t new_content_id) {
	// Allocate GpuMemoryBuffer if necessary. If using partial raster, we
	// must allocate a buffer with BufferUsage CPU_READ_WRITE_PERSISTENT.
	if (!staging_buffer->gpu_memory_buffer) {
	staging_buffer->gpu_memory_buffer =
	resource_provider_->gpu_memory_buffer_manager()
	->AllocateGpuMemoryBuffer(
	staging_buffer->size, BufferFormat(resource->format()),
	use_partial_raster_
	? gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT
	: gfx::BufferUsage::GPU_READ_CPU_READ_WRITE,
	gpu::kNullSurfaceHandle);
	}

	gfx::Rect playback_rect = raster_full_rect;
	if (use_partial_raster_ && previous_content_id) {
	// Reduce playback rect to dirty region if the content id of the staging
	// buffer matches the prevous content id.
	if (previous_content_id == staging_buffer->content_id)
	playback_rect.Intersect(raster_dirty_rect);
	}

	if (staging_buffer->gpu_memory_buffer) {
	gfx::GpuMemoryBuffer* buffer = staging_buffer->gpu_memory_buffer.get();
	DCHECK_EQ(1u, gfx::NumberOfPlanesForBufferFormat(buffer->GetFormat()));
	bool rv = buffer->Map();
	DCHECK(rv);
	DCHECK(buffer->memory(0));
	// RasterBufferProvider::PlaybackToMemory only supports unsigned strides.
	DCHECK_GE(buffer->stride(0), 0);

	DCHECK(!playback_rect.IsEmpty())
	<< "Why are we rastering a tile that's not dirty?";
	RasterBufferProvider::PlaybackToMemory(
	buffer->memory(0), resource->format(), staging_buffer->size,
	buffer->stride(0), raster_source, raster_full_rect, playback_rect,
	scale, playback_settings);
	buffer->Unmap();
	staging_buffer->content_id = new_content_id;
	}
	}

	void OneCopyRasterBufferProvider::CopyOnWorkerThread(
	StagingBuffer* staging_buffer,
	const Resource* resource,
	ResourceProvider::ScopedWriteLockGL* resource_lock,
	const RasterSource* raster_source,
	uint64_t previous_content_id,
	uint64_t new_content_id) {
	ContextProvider* context_provider =
	resource_provider_->output_surface()->worker_context_provider();
	DCHECK(context_provider);

	{
	ContextProvider::ScopedContextLock scoped_context(context_provider);

	gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
	DCHECK(gl);

	unsigned image_target =
	resource_provider_->GetImageTextureTarget(resource->format());

	// Create and bind staging texture.
	if (!staging_buffer->texture_id) {
	gl->GenTextures(1, &staging_buffer->texture_id);
	gl->BindTexture(image_target, staging_buffer->texture_id);
	gl->TexParameteri(image_target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	gl->TexParameteri(image_target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	gl->TexParameteri(image_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	gl->TexParameteri(image_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	} else {
	gl->BindTexture(image_target, staging_buffer->texture_id);
	}

	// Create and bind image.
	if (!staging_buffer->image_id) {
	if (staging_buffer->gpu_memory_buffer) {
	staging_buffer->image_id = gl->CreateImageCHROMIUM(
	staging_buffer->gpu_memory_buffer->AsClientBuffer(),
	staging_buffer->size.width(), staging_buffer->size.height(),
	GLInternalFormat(resource->format()));
	gl->BindTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
	}
	} else {
	gl->ReleaseTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
	gl->BindTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
	}

	// Unbind staging texture.
	gl->BindTexture(image_target, 0);

	if (resource_provider_->use_sync_query()) {
	if (!staging_buffer->query_id)
	gl->GenQueriesEXT(1, &staging_buffer->query_id);

	#if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY)
	// TODO(reveman): This avoids a performance problem on ARM ChromeOS
	// devices. crbug.com/580166
	gl->BeginQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM, staging_buffer->query_id);
	#else
	gl->BeginQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM,
	staging_buffer->query_id);
	#endif
	}

	// Since compressed texture's cannot be pre-allocated we might have an
	// unallocated resource in which case we need to perform a full size copy.
	if (IsResourceFormatCompressed(resource->format())) {
	gl->CompressedCopyTextureCHROMIUM(staging_buffer->texture_id,
	resource_lock->texture_id());
	} else {
	int bytes_per_row = ResourceUtil::UncheckedWidthInBytes<int>(
	resource->size().width(), resource->format());
	int chunk_size_in_rows =
	std::max(1, max_bytes_per_copy_operation_ / bytes_per_row);
	// Align chunk size to 4. Required to support compressed texture formats.
	chunk_size_in_rows = MathUtil::UncheckedRoundUp(chunk_size_in_rows, 4);
	int y = 0;
	int height = resource->size().height();
	while (y < height) {
	// Copy at most \|chunk_size_in_rows\|.
	int rows_to_copy = std::min(chunk_size_in_rows, height - y);
	DCHECK_GT(rows_to_copy, 0);

	gl->CopySubTextureCHROMIUM(
	staging_buffer->texture_id, resource_lock->texture_id(), 0, y, 0, y,
	resource->size().width(), rows_to_copy, false, false, false);
	y += rows_to_copy;

	// Increment \|bytes_scheduled_since_last_flush_\| by the amount of memory
	// used for this copy operation.
	bytes_scheduled_since_last_flush_ += rows_to_copy * bytes_per_row;

	if (bytes_scheduled_since_last_flush_ >=
	max_bytes_per_copy_operation_) {
	gl->ShallowFlushCHROMIUM();
	bytes_scheduled_since_last_flush_ = 0;
	}
	}
	}

	if (resource_provider_->use_sync_query()) {
	#if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY)
	gl->EndQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM);
	#else
	gl->EndQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM);
	#endif
	}

	const uint64_t fence_sync = gl->InsertFenceSyncCHROMIUM();

	// Barrier to sync worker context output to cc context.
	gl->OrderingBarrierCHROMIUM();

	// Generate sync token after the barrier for cross context synchronization.
	gpu::SyncToken sync_token;
	gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
	resource_lock->UpdateResourceSyncToken(sync_token);
	}
	}

	} // namespace cc