cc: Simplify task and its derived classes.

cc/raster/bitmap_tile_task_worker_pool.h

 // 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.
 
 #ifndef CC_RASTER_BITMAP_TILE_TASK_WORKER_POOL_H_
 #define CC_RASTER_BITMAP_TILE_TASK_WORKER_POOL_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/values.h"
 #include "cc/raster/tile_task_runner.h"
 #include "cc/raster/tile_task_worker_pool.h"
 
 namespace base {
 namespace trace_event {
 class ConvertableToTraceFormat;
 }
 }
 
 namespace cc {
 class ResourceProvider;
 
 class CC_EXPORT BitmapTileTaskWorkerPool : public TileTaskWorkerPool,
-                                           public TileTaskRunner,
-                                           public TileTaskClient {
+                                           public TileTaskRunner {
  public:
   ~BitmapTileTaskWorkerPool() override;
 
   static scoped_ptr<TileTaskWorkerPool> Create(
       base::SequencedTaskRunner* task_runner,
       TaskGraphRunner* task_graph_runner,
       ResourceProvider* resource_provider);
 
   // Overridden from TileTaskWorkerPool:
   TileTaskRunner* AsTileTaskRunner() override;
 
+  // Overridden from RasterBufferProvider:
+  scoped_ptr<RasterBuffer> AcquireBufferForRaster(
+      const Resource* resource,
+      uint64_t resource_content_id,
+      uint64_t previous_content_id) override;
+  void ReleaseBufferForRaster(scoped_ptr<RasterBuffer> buffer) override;
+
   // Overridden from TileTaskRunner:
   void Shutdown() override;
   void ScheduleTasks(TaskGraph* graph) override;
   void CheckForCompletedTasks() override;
   ResourceFormat GetResourceFormat(bool must_support_alpha) const override;
   bool GetResourceRequiresSwizzle(bool must_support_alpha) const override;
 
-  // Overridden from TileTaskClient:
-  scoped_ptr<RasterBuffer> AcquireBufferForRaster(
-      const Resource* resource,
-      uint64_t resource_content_id,
-      uint64_t previous_content_id) override;
-  void ReleaseBufferForRaster(scoped_ptr<RasterBuffer> buffer) override;
-
  protected:
   BitmapTileTaskWorkerPool(base::SequencedTaskRunner* task_runner,
                            TaskGraphRunner* task_graph_runner,
                            ResourceProvider* resource_provider);
 
  private:
   scoped_ptr<base::trace_event::ConvertableToTraceFormat> StateAsValue() const;
 
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   TaskGraphRunner* task_graph_runner_;
   const NamespaceToken namespace_token_;
   ResourceProvider* resource_provider_;
 
   Task::Vector completed_tasks_;
 
   DISALLOW_COPY_AND_ASSIGN(BitmapTileTaskWorkerPool);
 };
 
 }  // namespace cc
 
 #endif  // CC_RASTER_BITMAP_TILE_TASK_WORKER_POOL_H_