cc: Hook vsync time source to output surface

cc/trees/layer_tree_host_impl_unittest.cc

Index: cc/trees/layer_tree_host_impl_unittest.cc
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 8f412565b6deff37e1d5bb3cde73b7b953005ef5..dfd5e7a601dad1a4f3e9d4470b3c20e32a887729 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -91,6 +91,7 @@ class LayerTreeHostImplTest : public testing::Test,
   virtual void OnSwapBuffersCompleteOnImplThread() OVERRIDE {}
   virtual void OnVSyncParametersChanged(base::TimeTicks timebase,
                                         base::TimeDelta interval) OVERRIDE {}
+  virtual void DidVSync(base::TimeTicks frame_time) OVERRIDE {}
   virtual void OnCanDrawStateChanged(bool can_draw) OVERRIDE {
     on_can_draw_state_changed_called_ = true;
   }