cc: GPU rasterize tiles synchronously in PrepareToDraw

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 900e658bc96e925bb14f820d29aa1d46a3575165..484068b5bc6a5e5681da3fbc37d10bdf1babcaae 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -51,6 +51,7 @@ class PaintTimeCounter;
 class PictureLayerImpl;
 class RasterTilePriorityQueue;
 class RasterWorkerPool;
+class GpuRasterizer;
 class RenderPassDrawQuad;
 class RenderingStatsInstrumentation;
 class ResourcePool;
@@ -191,6 +192,7 @@ class CC_EXPORT LayerTreeHostImpl
   void DidAnimateScrollOffset();
   void SetViewportDamage(const gfx::Rect& damage_rect);
 
+  virtual void RasterizeTiles();
   virtual void ManageTiles();
 
   // Returns DRAW_SUCCESS unless problems occured preparing the frame, and we
@@ -483,6 +485,7 @@ class CC_EXPORT LayerTreeHostImpl
 
   virtual void CreateResourceAndRasterWorkerPool(
       scoped_ptr<RasterWorkerPool>* raster_worker_pool,
+      scoped_ptr<GpuRasterizer>* gpu_rasterizer,
       scoped_ptr<ResourcePool>* resource_pool,
       scoped_ptr<ResourcePool>* staging_resource_pool);
 
@@ -592,6 +595,7 @@ class CC_EXPORT LayerTreeHostImpl
   scoped_ptr<TileManager> tile_manager_;
   bool use_gpu_rasterization_;
   scoped_ptr<RasterWorkerPool> raster_worker_pool_;
+  scoped_ptr<GpuRasterizer> gpu_rasterizer_;
   scoped_ptr<ResourcePool> resource_pool_;
   scoped_ptr<ResourcePool> staging_resource_pool_;
   scoped_ptr<Renderer> renderer_;