Make cc output surface creation async

cc/trees/layer_tree_host_client.h

Index: cc/trees/layer_tree_host_client.h
diff --git a/cc/trees/layer_tree_host_client.h b/cc/trees/layer_tree_host_client.h
index 73ec892268983fff97569251edaa6ef0b0b4d628..95480eff0ae1b576779a4b396d3115e6bb4c15d4 100644
--- a/cc/trees/layer_tree_host_client.h
+++ b/cc/trees/layer_tree_host_client.h
@@ -30,9 +30,11 @@ class LayerTreeHostClient {
   virtual void ApplyViewportDeltas(const gfx::Vector2d& scroll_delta,
                                    float page_scale,
                                    float top_controls_delta) = 0;
-  // Creates an OutputSurface. If fallback is true, it should attempt to
-  // create an OutputSurface that is guaranteed to initialize correctly.
-  virtual scoped_ptr<OutputSurface> CreateOutputSurface(bool fallback) = 0;
+  // Request an OutputSurface from the client. When the client has one it should
+  // call LayerTreeHost::SetOutputSurface.  If fallback is true, it should
+  // attempt to create an OutputSurface that is guaranteed to initialize
+  // correctly.
+  virtual void RequestNewOutputSurface(bool fallback) = 0;
   virtual void DidInitializeOutputSurface() = 0;
   virtual void WillCommit() = 0;
   virtual void DidCommit() = 0;