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 74dcbc0cff24631873737c4cdc42341e1051f4ed..326f5c86c41aa6156f0a617cbd214e4a56d38e37 100644
--- a/cc/trees/layer_tree_host_client.h
+++ b/cc/trees/layer_tree_host_client.h
@@ -28,9 +28,11 @@ class LayerTreeHostClient {
   virtual void Layout() = 0;
   virtual void ApplyScrollAndScale(const gfx::Vector2d& scroll_delta,
                                    float page_scale) = 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;