CC Animation: Let MutatorHostClient deals with elements instead of layers.

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 8e50cbba0fc21c0373078582f6f764d5c8186df9..ae4f257a973e4cb4fa14aca9722acd812eb07b8c 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -257,28 +257,31 @@ class CC_EXPORT LayerTreeHostImpl
                                                        bool is_animating);
   bool AnimationsPreserveAxisAlignment(const LayerImpl* layer) const;
 
-  // LayerTreeMutatorsClient implementation.
-  bool IsLayerInTree(int layer_id, LayerTreeType tree_type) const override;
+  // MutatorHostClient implementation.
+  bool IsElementInList(ElementId element_id,
+                       ElementListType list_type) const override;
   void SetMutatorsNeedCommit() override;
   void SetMutatorsNeedRebuildPropertyTrees() override;
-  void SetLayerFilterMutated(int layer_id,
-                             LayerTreeType tree_type,
-                             const FilterOperations& filters) override;
-  void SetLayerOpacityMutated(int layer_id,
-                              LayerTreeType tree_type,
-                              float opacity) override;
-  void SetLayerTransformMutated(int layer_id,
-                                LayerTreeType tree_type,
-                                const gfx::Transform& transform) override;
-  void SetLayerScrollOffsetMutated(
-      int layer_id,
-      LayerTreeType tree_type,
+  void SetElementFilterMutated(ElementId element_id,
+                               ElementListType list_type,
+                               const FilterOperations& filters) override;
+  void SetElementOpacityMutated(ElementId element_id,
+                                ElementListType list_type,
+                                float opacity) override;
+  void SetElementTransformMutated(ElementId element_id,
+                                  ElementListType list_type,
+                                  const gfx::Transform& transform) override;
+  void SetElementScrollOffsetMutated(
+      ElementId element_id,
+      ElementListType list_type,
       const gfx::ScrollOffset& scroll_offset) override;
-  void LayerTransformIsPotentiallyAnimatingChanged(int layer_id,
-                                                   LayerTreeType tree_type,
-                                                   bool is_animating) override;
+  void ElementTransformIsPotentiallyAnimatingChanged(
+      ElementId element_id,
+      ElementListType list_type,
+      bool is_animating) override;
   void ScrollOffsetAnimationFinished() override;
-  gfx::ScrollOffset GetScrollOffsetForAnimation(int layer_id) const override;
+  gfx::ScrollOffset GetScrollOffsetForAnimation(
+      ElementId element_id) const override;
 
   virtual bool PrepareTiles();