Allow task pools to reason about transparency.

cc/raster/one_copy_tile_task_worker_pool.h

Index: cc/raster/one_copy_tile_task_worker_pool.h
diff --git a/cc/raster/one_copy_tile_task_worker_pool.h b/cc/raster/one_copy_tile_task_worker_pool.h
index 783d103c850ac1f44c008591ee8a7bbc44b50c65..dececdb7294af05785949551ea1734a14557a88d 100644
--- a/cc/raster/one_copy_tile_task_worker_pool.h
+++ b/cc/raster/one_copy_tile_task_worker_pool.h
@@ -59,8 +59,8 @@ class CC_EXPORT OneCopyTileTaskWorkerPool
   void Shutdown() override;
   void ScheduleTasks(TileTaskQueue* queue) override;
   void CheckForCompletedTasks() override;
-  ResourceFormat GetResourceFormat() const override;
-  bool GetResourceRequiresSwizzle() const override;
+  ResourceFormat GetResourceFormat(bool must_support_alpha) const override;
+  bool GetResourceRequiresSwizzle(bool must_support_alpha) const override;
 
   // Overridden from TileTaskClient:
   scoped_ptr<RasterBuffer> AcquireBufferForRaster(
@@ -112,7 +112,8 @@ class CC_EXPORT OneCopyTileTaskWorkerPool
     uint64_t content_id;
   };
 
-  void AddStagingBuffer(const StagingBuffer* staging_buffer);
+  void AddStagingBuffer(const StagingBuffer* staging_buffer,
+                        ResourceFormat format);
   void RemoveStagingBuffer(const StagingBuffer* staging_buffer);
   void MarkStagingBufferAsFree(const StagingBuffer* staging_buffer);
   void MarkStagingBufferAsBusy(const StagingBuffer* staging_buffer);