[DRAFT] Animations: Profile hash look-ups for external mutators

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 <set>
 #include <string>
 #include <vector>
@@ skipping 232 matching lines @@
   gfx::SizeF ScrollableViewportSize() const;
 
   gfx::Rect RootScrollLayerDeviceViewportBounds() const;
 
   LayerImpl* LayerById(int id) const;
 
   // These should be called by LayerImpl's ctor/dtor.
   void RegisterLayer(LayerImpl* layer);
   void UnregisterLayer(LayerImpl* layer);
 
+  base::TimeDelta find_layer_by_id_stats() const {
+    return find_layer_by_id_stats_;
+  }
+  void ClearStatsOnFrameEnd();
+
   size_t NumLayers();
 
   AnimationRegistrar* GetAnimationRegistrar() const;
 
   void PushPersistedState(LayerTreeImpl* pending_tree);
 
   void DidBecomeActive();
 
   bool ContentsTexturesPurged() const;
   void SetContentsTexturesPurged();
@@ skipping 143 matching lines @@
   LayerSelection selection_;
 
   scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor_;
   float min_page_scale_factor_;
   float max_page_scale_factor_;
 
   scoped_refptr<SyncedElasticOverscroll> elastic_overscroll_;
 
   typedef base::hash_map<int, LayerImpl*> LayerIdMap;
   LayerIdMap layer_id_map_;
+  mutable base::TimeDelta find_layer_by_id_stats_;
 
   std::vector<PictureLayerImpl*> picture_layers_;
   std::vector<LayerImpl*> layers_with_copy_output_request_;
 
   // Persisted state for non-impl-side-painting.
   int scrolling_layer_id_from_previous_tree_;
 
   // List of visible layers for the most recently prepared frame.
   LayerImplList render_surface_layer_list_;
   // After drawing the |render_surface_layer_list_| the areas in this region
@@ skipping 30 matching lines @@
 
   scoped_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_