cc: Simplify task and its derived classes.

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 f691232c33caee2269be9d2cf7e838059312de1d..fbf53abbb77c28bf026d6c22c94d3fdee9df461b 100644
--- a/cc/raster/one_copy_tile_task_worker_pool.h
+++ b/cc/raster/one_copy_tile_task_worker_pool.h
@@ -40,7 +40,6 @@ class ResourcePool;
 class CC_EXPORT OneCopyTileTaskWorkerPool
     : public TileTaskWorkerPool,
       public TileTaskRunner,
-      public TileTaskClient,
       public base::trace_event::MemoryDumpProvider {
  public:
   ~OneCopyTileTaskWorkerPool() override;
@@ -58,6 +57,13 @@ class CC_EXPORT OneCopyTileTaskWorkerPool
   // 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;
@@ -65,13 +71,6 @@ class CC_EXPORT OneCopyTileTaskWorkerPool
   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;
-
   // Overridden from base::trace_event::MemoryDumpProvider:
   bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                     base::trace_event::ProcessMemoryDump* pmd) override;