Make cc output surface creation async

cc/test/layer_tree_test.h

Index: cc/test/layer_tree_test.h
diff --git a/cc/test/layer_tree_test.h b/cc/test/layer_tree_test.h
index 0f7aec35b9299ff181f82916e449a23c5ec22563..0fc35ca862aac202fe7e05d0c0fb5f986d88984e 100644
--- a/cc/test/layer_tree_test.h
+++ b/cc/test/layer_tree_test.h
@@ -93,7 +93,7 @@ class TestHooks : public AnimationDelegate {
       base::TimeTicks monotonic_time,
       Animation::TargetProperty target_property) OVERRIDE {}
 
-  virtual scoped_ptr<OutputSurface> CreateOutputSurface(bool fallback) = 0;
+  virtual void RequestNewOutputSurface(bool fallback) = 0;
 };
 
 class BeginTask;
@@ -182,8 +182,10 @@ class LayerTreeTest : public testing::Test, public TestHooks {
 
   void DestroyLayerTreeHost();
 
+  // By default, output surface recreation is synchronous.
+  virtual void RequestNewOutputSurface(bool fallback) OVERRIDE;
   // Override this for pixel tests, where you need a real output surface.
-  virtual scoped_ptr<OutputSurface> CreateOutputSurface(bool fallback) OVERRIDE;
+  virtual scoped_ptr<OutputSurface> CreateOutputSurface(bool fallback);
   // Override this for unit tests, which should not produce pixel output.
   virtual scoped_ptr<FakeOutputSurface> CreateFakeOutputSurface(bool fallback);