cc: Merge TileTaskRunner to TileTaskWorkerPool.

cc/raster/bitmap_tile_task_worker_pool.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/bitmap_tile_task_worker_pool.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 69 matching lines @@
     TaskGraphRunner* task_graph_runner,
     ResourceProvider* resource_provider)
     : task_runner_(task_runner),
       task_graph_runner_(task_graph_runner),
       namespace_token_(task_graph_runner->GetNamespaceToken()),
       resource_provider_(resource_provider) {}
 
 BitmapTileTaskWorkerPool::~BitmapTileTaskWorkerPool() {
 }
 
-TileTaskRunner* BitmapTileTaskWorkerPool::AsTileTaskRunner() {
-  return this;
-}
-
 void BitmapTileTaskWorkerPool::Shutdown() {
   TRACE_EVENT0("cc", "BitmapTileTaskWorkerPool::Shutdown");
 
   TaskGraph empty;
   task_graph_runner_->ScheduleTasks(namespace_token_, &empty);
   task_graph_runner_->WaitForTasksToFinishRunning(namespace_token_);
 }
 
 void BitmapTileTaskWorkerPool::ScheduleTasks(TaskGraph* graph) {
   TRACE_EVENT0("cc", "BitmapTileTaskWorkerPool::ScheduleTasks");
@@ skipping 39 matching lines @@
   return std::unique_ptr<RasterBuffer>(new RasterBufferImpl(
       resource_provider_, resource, resource_content_id, previous_content_id));
 }
 
 void BitmapTileTaskWorkerPool::ReleaseBufferForRaster(
     std::unique_ptr<RasterBuffer> buffer) {
   // Nothing to do here. RasterBufferImpl destructor cleans up after itself.
 }
 
 }  // namespace cc