Fixing flakiness of TextureLayerChangeInvisibleMailboxTest

cc/test/test_hooks.h

Index: cc/test/test_hooks.h
diff --git a/cc/test/test_hooks.h b/cc/test/test_hooks.h
index a7dc578356ca4f8ef4aa4c4efad3e50c1239d932..ade5f8093cb0bcefeffba9d7a33364e3218cc1b1 100644
--- a/cc/test/test_hooks.h
+++ b/cc/test/test_hooks.h
@@ -61,6 +61,8 @@ class TestHooks : public AnimationDelegate {
                                  base::TimeTicks monotonic_time) {}
   virtual void DidInvalidateContentOnImplSide(LayerTreeHostImpl* host_impl) {}
   virtual void DidRequestImplSideInvalidation(LayerTreeHostImpl* host_impl) {}
+  virtual void WillReceiveCompositorFrameAckOnImplThread() {}

[danakj, 2017/04/18 20:58:42]

just "OnThread" is the convention used here, and can you group it with the other
OnThread things just above?

[Saman Sami, 2017/04/18 21:37:13]

Done.

+  virtual void DidReceiveCompositorFrameAckOnImplThread() {}
 
   // Asynchronous compositor thread hooks.
   // These are called asynchronously from the LayerTreeHostImpl performing its