cc: LayerTreeHostImpl uses element id to tick animations

cc/trees/layer_tree_impl.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 127 matching lines @@
 
   void MoveChangeTrackingToLayers();
 
   void ForceRecalculateRasterScales();
 
   LayerImplList::const_iterator begin() const;
   LayerImplList::const_iterator end() const;
   LayerImplList::reverse_iterator rbegin();
   LayerImplList::reverse_iterator rend();
 
+  // TODO(crbug.com/702832): This won't be needed if overlay scrollbars have
+  // element ids.
   void AddToOpacityAnimationsMap(int id, float opacity);
-  void AddToTransformAnimationsMap(int id, gfx::Transform transform);
-  void AddToFilterAnimationsMap(int id, const FilterOperations& filters);
+
+  void SetTreeLayerTransformMutated(ElementId element_id,
+                                    const gfx::Transform& transform);
+  void SetTreeLayerOpacityMutated(ElementId element_id, float opacity);
+  void SetTreeLayerFilterMutated(ElementId element_id,

[ajuma, 2017/03/21 22:00:30]

Wdyt of removing 'TreeLayer' from these names since they just involve property
trees rather than layers now?

[weiliangc, 2017/03/22 18:44:15]

Done.

+                                 const FilterOperations& filters);
 
   int source_frame_number() const { return source_frame_number_; }
   void set_source_frame_number(int frame_number) {
     source_frame_number_ = frame_number;
   }
 
   bool is_first_frame_after_commit() const {
     return source_frame_number_ != is_first_frame_after_commit_tracker_;
   }
 
@@ skipping 416 matching lines @@
 
   std::unique_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_