cc : Track opacity animation changes on effect tree

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index c4795d0996e1ac36e97a06ff3469c3bf75b1c775..07d3f5ab74331422a33f0a768dbad6683c8ad30d 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -96,6 +96,8 @@ class CC_EXPORT LayerImpl {
   void OnTransformAnimated(const gfx::Transform& transform);
   void OnScrollOffsetAnimated(const gfx::ScrollOffset& scroll_offset);
   void OnTransformIsPotentiallyAnimatingChanged(bool is_animating);
+  void OnOpacityIsCurrentlyAnimatingChanged(bool is_currently_animating);
+  void OnOpacityIsPotentiallyAnimatingChanged(bool has_potential_animation);
   bool IsActive() const;
   bool OpacityCanAnimateOnImplThread() const { return false; }