Allow task pools to reason about transparency.

cc/raster/one_copy_tile_task_worker_pool.cc

Index: cc/raster/one_copy_tile_task_worker_pool.cc
diff --git a/cc/raster/one_copy_tile_task_worker_pool.cc b/cc/raster/one_copy_tile_task_worker_pool.cc
index c5518e3cd88d5a1e348f22dbce8d6c5cfb70d304..86a0561b1ca9ed585da8d4eabbf4bec62cdfa16d 100644
--- a/cc/raster/one_copy_tile_task_worker_pool.cc
+++ b/cc/raster/one_copy_tile_task_worker_pool.cc
@@ -100,8 +100,14 @@ void WaitForQueryResult(gpu::gles2::GLES2Interface* gl, unsigned query_id) {
 
 }  // namespace
 
-OneCopyTileTaskWorkerPool::StagingBuffer::StagingBuffer(const gfx::Size& size)
-    : size(size), texture_id(0), image_id(0), query_id(0), content_id(0) {}
+OneCopyTileTaskWorkerPool::StagingBuffer::StagingBuffer(const gfx::Size& size,
+                                                        ResourceFormat format)
+    : size(size),
+      format(format),
+      texture_id(0),
+      image_id(0),
+      query_id(0),
+      content_id(0) {}
 
 OneCopyTileTaskWorkerPool::StagingBuffer::~StagingBuffer() {
   DCHECK_EQ(texture_id, 0u);
@@ -169,11 +175,12 @@ scoped_ptr<TileTaskWorkerPool> OneCopyTileTaskWorkerPool::Create(
     ResourceProvider* resource_provider,
     int max_copy_texture_chromium_size,
     bool use_persistent_gpu_memory_buffers,
-    int max_staging_buffer_usage_in_bytes) {
+    int max_staging_buffer_usage_in_bytes,
+    bool use_rgba_4444_texture_format) {
   return make_scoped_ptr<TileTaskWorkerPool>(new OneCopyTileTaskWorkerPool(
       task_runner, task_graph_runner, resource_provider,
       max_copy_texture_chromium_size, use_persistent_gpu_memory_buffers,
-      max_staging_buffer_usage_in_bytes));
+      max_staging_buffer_usage_in_bytes, use_rgba_4444_texture_format));
 }
 
 OneCopyTileTaskWorkerPool::OneCopyTileTaskWorkerPool(
@@ -182,7 +189,8 @@ OneCopyTileTaskWorkerPool::OneCopyTileTaskWorkerPool(
     ResourceProvider* resource_provider,
     int max_copy_texture_chromium_size,
     bool use_persistent_gpu_memory_buffers,
-    int max_staging_buffer_usage_in_bytes)
+    int max_staging_buffer_usage_in_bytes,
+    bool use_rgba_4444_texture_format)
     : task_runner_(task_runner),
       task_graph_runner_(task_graph_runner),
       namespace_token_(task_graph_runner->GetNamespaceToken()),
@@ -195,6 +203,7 @@ OneCopyTileTaskWorkerPool::OneCopyTileTaskWorkerPool(
       use_persistent_gpu_memory_buffers_(use_persistent_gpu_memory_buffers),
       bytes_scheduled_since_last_flush_(0),
       max_staging_buffer_usage_in_bytes_(max_staging_buffer_usage_in_bytes),
+      use_rgba_4444_texture_format_(use_rgba_4444_texture_format),
       staging_buffer_usage_in_bytes_(0),
       free_staging_buffer_usage_in_bytes_(0),
       staging_buffer_expiration_delay_(
@@ -326,12 +335,17 @@ void OneCopyTileTaskWorkerPool::CheckForCompletedTasks() {
   completed_tasks_.clear();
 }
 
-ResourceFormat OneCopyTileTaskWorkerPool::GetResourceFormat() const {
-  return resource_provider_->memory_efficient_texture_format();
+ResourceFormat OneCopyTileTaskWorkerPool::GetResourceFormat(
+    bool must_support_alpha) const {
+  return use_rgba_4444_texture_format_
+             ? RGBA_4444
+             : resource_provider_->best_texture_format();
 }
 
-bool OneCopyTileTaskWorkerPool::GetResourceRequiresSwizzle() const {
-  return !PlatformColor::SameComponentOrder(GetResourceFormat());
+bool OneCopyTileTaskWorkerPool::GetResourceRequiresSwizzle(
+    bool must_support_alpha) const {
+  return !PlatformColor::SameComponentOrder(
+      GetResourceFormat(must_support_alpha));
 }
 
 scoped_ptr<RasterBuffer> OneCopyTileTaskWorkerPool::AcquireBufferForRaster(
@@ -340,12 +354,9 @@ scoped_ptr<RasterBuffer> OneCopyTileTaskWorkerPool::AcquireBufferForRaster(
     uint64_t previous_content_id) {
   // TODO(danakj): If resource_content_id != 0, we only need to copy/upload
   // the dirty rect.
-  DCHECK_EQ(resource->format(),
-            resource_provider_->memory_efficient_texture_format());
-  return make_scoped_ptr<RasterBuffer>(new RasterBufferImpl(
-      this, resource_provider_,
-      resource_provider_->memory_efficient_texture_format(), resource,
-      previous_content_id));
+  return make_scoped_ptr<RasterBuffer>(
+      new RasterBufferImpl(this, resource_provider_, resource->format(),
+                           resource, previous_content_id));
 }
 
 void OneCopyTileTaskWorkerPool::ReleaseBufferForRaster(
@@ -376,13 +387,11 @@ void OneCopyTileTaskWorkerPool::PlaybackAndCopyOnWorkerThread(
     if (!staging_buffer->gpu_memory_buffer) {
       staging_buffer->gpu_memory_buffer =
           resource_provider_->gpu_memory_buffer_manager()
-              ->AllocateGpuMemoryBuffer(
-                  staging_buffer->size,
-                  BufferFormat(
-                      resource_provider_->memory_efficient_texture_format()),
-                  use_persistent_gpu_memory_buffers_
-                      ? gfx::BufferUsage::PERSISTENT_MAP
-                      : gfx::BufferUsage::MAP);
+              ->AllocateGpuMemoryBuffer(staging_buffer->size,
+                                        BufferFormat(resource->format()),
+                                        use_persistent_gpu_memory_buffers_
+                                            ? gfx::BufferUsage::PERSISTENT_MAP
+                                            : gfx::BufferUsage::MAP);
       DCHECK_EQ(gfx::NumberOfPlanesForBufferFormat(
                     staging_buffer->gpu_memory_buffer->GetFormat()),
                 1u);
@@ -408,9 +417,9 @@ void OneCopyTileTaskWorkerPool::PlaybackAndCopyOnWorkerThread(
       DCHECK(!playback_rect.IsEmpty())
           << "Why are we rastering a tile that's not dirty?";
       TileTaskWorkerPool::PlaybackToMemory(
-          data, resource_provider_->memory_efficient_texture_format(),
-          staging_buffer->size, static_cast<size_t>(stride), raster_source,
-          raster_full_rect, playback_rect, scale, include_images);
+          data, resource->format(), staging_buffer->size,
+          static_cast<size_t>(stride), raster_source, raster_full_rect,
+          playback_rect, scale, include_images);
       staging_buffer->gpu_memory_buffer->Unmap();
       staging_buffer->content_id = new_content_id;
     }
@@ -426,8 +435,8 @@ void OneCopyTileTaskWorkerPool::PlaybackAndCopyOnWorkerThread(
     gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
     DCHECK(gl);
 
-    unsigned image_target = resource_provider_->GetImageTextureTarget(
-        resource_provider_->memory_efficient_texture_format());
+    unsigned image_target =
+        resource_provider_->GetImageTextureTarget(resource->format());
 
     // Create and bind staging texture.
     if (!staging_buffer->texture_id) {
@@ -447,8 +456,7 @@ void OneCopyTileTaskWorkerPool::PlaybackAndCopyOnWorkerThread(
         staging_buffer->image_id = gl->CreateImageCHROMIUM(
             staging_buffer->gpu_memory_buffer->AsClientBuffer(),
             staging_buffer->size.width(), staging_buffer->size.height(),
-            GLInternalFormat(
-                resource_provider_->memory_efficient_texture_format()));
+            GLInternalFormat(resource->format()));
         gl->BindTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
       }
     } else {
@@ -475,9 +483,7 @@ void OneCopyTileTaskWorkerPool::PlaybackAndCopyOnWorkerThread(
     }
 
     int bytes_per_row =
-        (BitsPerPixel(resource_provider_->memory_efficient_texture_format()) *
-         resource->size().width()) /
-        8;
+        (BitsPerPixel(resource->format()) * resource->size().width()) / 8;
     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.
@@ -529,8 +535,7 @@ bool OneCopyTileTaskWorkerPool::OnMemoryDump(
   base::AutoLock lock(lock_);
 
   for (const auto& buffer : buffers_) {
-    buffer->OnMemoryDump(pmd,
-                         resource_provider_->memory_efficient_texture_format(),
+    buffer->OnMemoryDump(pmd, buffer->format,
                          std::find(free_buffers_.begin(), free_buffers_.end(),
                                    buffer) != free_buffers_.end());
   }
@@ -539,14 +544,14 @@ bool OneCopyTileTaskWorkerPool::OnMemoryDump(
 }
 
 void OneCopyTileTaskWorkerPool::AddStagingBuffer(
-    const StagingBuffer* staging_buffer) {
+    const StagingBuffer* staging_buffer,
+    ResourceFormat format) {
   lock_.AssertAcquired();
 
   DCHECK(buffers_.find(staging_buffer) == buffers_.end());
   buffers_.insert(staging_buffer);
-  int buffer_usage_in_bytes = ResourceUtil::UncheckedSizeInBytes<int>(
-      staging_buffer->size,
-      resource_provider_->memory_efficient_texture_format());
+  int buffer_usage_in_bytes =
+      ResourceUtil::UncheckedSizeInBytes<int>(staging_buffer->size, format);
   staging_buffer_usage_in_bytes_ += buffer_usage_in_bytes;
 }
 
@@ -557,8 +562,7 @@ void OneCopyTileTaskWorkerPool::RemoveStagingBuffer(
   DCHECK(buffers_.find(staging_buffer) != buffers_.end());
   buffers_.erase(staging_buffer);
   int buffer_usage_in_bytes = ResourceUtil::UncheckedSizeInBytes<int>(
-      staging_buffer->size,
-      resource_provider_->memory_efficient_texture_format());
+      staging_buffer->size, staging_buffer->format);
   DCHECK_GE(staging_buffer_usage_in_bytes_, buffer_usage_in_bytes);
   staging_buffer_usage_in_bytes_ -= buffer_usage_in_bytes;
 }
@@ -568,8 +572,7 @@ void OneCopyTileTaskWorkerPool::MarkStagingBufferAsFree(
   lock_.AssertAcquired();
 
   int buffer_usage_in_bytes = ResourceUtil::UncheckedSizeInBytes<int>(
-      staging_buffer->size,
-      resource_provider_->memory_efficient_texture_format());
+      staging_buffer->size, staging_buffer->format);
   free_staging_buffer_usage_in_bytes_ += buffer_usage_in_bytes;
 }
 
@@ -578,8 +581,7 @@ void OneCopyTileTaskWorkerPool::MarkStagingBufferAsBusy(
   lock_.AssertAcquired();
 
   int buffer_usage_in_bytes = ResourceUtil::UncheckedSizeInBytes<int>(
-      staging_buffer->size,
-      resource_provider_->memory_efficient_texture_format());
+      staging_buffer->size, staging_buffer->format);
   DCHECK_GE(free_staging_buffer_usage_in_bytes_, buffer_usage_in_bytes);
   free_staging_buffer_usage_in_bytes_ -= buffer_usage_in_bytes;
 }
@@ -647,12 +649,13 @@ OneCopyTileTaskWorkerPool::AcquireStagingBuffer(const Resource* resource,
     }
   }
 
-  // Find staging buffer of correct size.
+  // Find staging buffer of correct size and format.
   if (!staging_buffer) {
     StagingBufferDeque::iterator it =
         std::find_if(free_buffers_.begin(), free_buffers_.end(),
                      [resource](const StagingBuffer* buffer) {
-                       return buffer->size == resource->size();
+                       return buffer->size == resource->size() &&
+                              buffer->format == resource->format();
                      });
     if (it != free_buffers_.end()) {
       staging_buffer = free_buffers_.take(it);
@@ -662,8 +665,9 @@ OneCopyTileTaskWorkerPool::AcquireStagingBuffer(const Resource* resource,
 
   // Create new staging buffer if necessary.
   if (!staging_buffer) {
-    staging_buffer = make_scoped_ptr(new StagingBuffer(resource->size()));
-    AddStagingBuffer(staging_buffer.get());
+    staging_buffer = make_scoped_ptr(
+        new StagingBuffer(resource->size(), resource->format()));
+    AddStagingBuffer(staging_buffer.get(), resource->format());
   }
 
   // Release enough free buffers to stay within the limit.