Make cc output surface creation async

cc/trees/proxy.h

Index: cc/trees/proxy.h
diff --git a/cc/trees/proxy.h b/cc/trees/proxy.h
index 4066513773c01c0efba5fb200e1bf1d55a7c82cf..8b0e2429d6eb739e92b50f22160f2405f9742d18 100644
--- a/cc/trees/proxy.h
+++ b/cc/trees/proxy.h
@@ -52,6 +52,8 @@ class CC_EXPORT Proxy {
 
   virtual bool IsStarted() const = 0;
 
+  virtual void SetOutputSurface(scoped_ptr<OutputSurface>) = 0;

[danakj, 2014/06/25 17:43:09]

Can you add comment about how this will cause
LayerTreeHost::OnCreateAndInitializeOutputSurfaceAttempted to be called with the
result.

[enne (OOO), 2014/06/25 21:25:05]

Done.  After this patch, I want to revist that and maybe just have LTH call it
directly (since this is really indirect).

[danakj, 2014/06/25 21:25:50]

+1

+
   // Indicates that the compositing surface associated with our context is
   // ready to use.
   virtual void SetLayerTreeHostClientReady() = 0;