cc: Switch RenderingStats collection in Layer::Update() to RenderingStatsInstrumentation

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 081a1e1a8d67d60ab6ce111685fa91968b5fa49f..c2fa0eef36d15cd3cd08e2252db65bb42d162f57 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -440,13 +440,6 @@ class CC_EXPORT LayerTreeHostImpl : public InputHandlerClient,
   scoped_ptr<MemoryHistory> memory_history_;
   scoped_ptr<DebugRectHistory> debug_rect_history_;
 
-  int64 num_impl_thread_scrolls_;
-  int64 num_main_thread_scrolls_;
-
-  int64 cumulative_num_layers_drawn_;
-
-  int64 cumulative_num_missing_tiles_;
-
   size_t last_sent_memory_visible_bytes_;
   size_t last_sent_memory_visible_and_nearby_bytes_;
   size_t last_sent_memory_use_bytes_;