Re-land: cc: Use worker context for one-copy tile initialization.

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 01f8792092ddaadd18b83581ca811744f5b2c1bc..6d6c2ffe3bc2bf86b97865c48740da77ead4fc04 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -552,8 +552,7 @@ class CC_EXPORT LayerTreeHostImpl
 
   virtual void CreateResourceAndTileTaskWorkerPool(
       scoped_ptr<TileTaskWorkerPool>* tile_task_worker_pool,
-      scoped_ptr<ResourcePool>* resource_pool,
-      scoped_ptr<ResourcePool>* staging_resource_pool);
+      scoped_ptr<ResourcePool>* resource_pool);
 
   bool prepare_tiles_needed() const { return tile_priorities_dirty_; }
 
@@ -706,7 +705,6 @@ class CC_EXPORT LayerTreeHostImpl
   bool tree_resources_for_gpu_rasterization_dirty_;
   scoped_ptr<TileTaskWorkerPool> tile_task_worker_pool_;
   scoped_ptr<ResourcePool> resource_pool_;
-  scoped_ptr<ResourcePool> staging_resource_pool_;
   scoped_ptr<Renderer> renderer_;
 
   GlobalStateThatImpactsTilePriority global_tile_state_;