cc: Refactor TileTaskWorkerPool.

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index ba9b674e4077d8f20e9c4efea81281da030e6dcd..4ca0bb2429a29e51d8e666c5d5d662ca134f572c 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -65,6 +65,7 @@ class MemoryHistory;
 class PageScaleAnimation;
 class PictureLayerImpl;
 class RasterTilePriorityQueue;
+class TileTaskManager;
 class TileTaskWorkerPool;
 class RenderPassDrawQuad;
 class RenderingStatsInstrumentation;
@@ -758,7 +759,7 @@ class CC_EXPORT LayerTreeHostImpl
   bool use_msaa_;
   GpuRasterizationStatus gpu_rasterization_status_;
   bool tree_resources_for_gpu_rasterization_dirty_;
-  std::unique_ptr<TileTaskWorkerPool> tile_task_worker_pool_;
+  std::unique_ptr<TileTaskManager> tile_task_manager_;
   std::unique_ptr<ResourcePool> resource_pool_;
   std::unique_ptr<Renderer> renderer_;
   std::unique_ptr<ImageDecodeController> image_decode_controller_;