cc : Use effect node data to determine which opacity wins at commit.

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index c671e31b83b5776ca25afe362111794f77d0e9fe..bf4ccf59c2880bcc76e0b38a0dd95d3f89eda686 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -170,6 +170,9 @@ class CC_EXPORT LayerTreeImpl {
 
   void AddToElementMap(LayerImpl* layer);
   void RemoveFromElementMap(LayerImpl* layer);
+
+  void AddToOpacityAnimationsMap(int id, float opacity);
+
   ElementLayers GetMutableLayers(uint64_t element_id);
   int source_frame_number() const { return source_frame_number_; }
   void set_source_frame_number(int frame_number) {
@@ -534,6 +537,8 @@ class CC_EXPORT LayerTreeImpl {
 
   std::unordered_map<uint64_t, ElementLayers> element_layers_map_;
 
+  std::unordered_map<int, float> opacity_animations_map_;
+
   // Maps from clip layer ids to scroll layer ids.  Note that this only includes
   // the subset of clip layers that act as scrolling containers.  (This is
   // derived from LayerImpl::scroll_clip_layer_ and exists to avoid O(n) walks.)