cc : Add subtree is hidden bool to effect tree

cc/trees/property_tree.h

Index: cc/trees/property_tree.h
diff --git a/cc/trees/property_tree.h b/cc/trees/property_tree.h
index 8b94fe9c3bdcb67dedadb5e5ef2693bbdf699999..64247f02cc0edfbc9dc543c20caa99b6994ad739 100644
--- a/cc/trees/property_tree.h
+++ b/cc/trees/property_tree.h
@@ -270,6 +270,9 @@ struct CC_EXPORT EffectNodeData {
   bool hidden_by_backface_visibility;
   bool double_sided;
   bool is_drawn;
+  // TODO(jaydasika) : Delete this after implementation of
+  // SetHideLayerAndSubtree is cleaned up. (crbug.com/595843)
+  bool subtree_hidden;
   bool has_animated_opacity;
   // We need to track changes to effects on the compositor to compute damage
   // rect.
@@ -548,6 +551,8 @@ class CC_EXPORT EffectTree final : public PropertyTree<EffectNode> {
  public:
   bool operator==(const EffectTree& other) const;
 
+  float EffectiveOpacity(const EffectNode* node) const;
+
   void UpdateEffects(int id);
 
   void UpdateEffectChanged(EffectNode* node, EffectNode* parent_node);