Implement scroll handler latency tracking

cc/trees/layer_tree_host_impl.h

 // Copyright 2011 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_HOST_IMPL_H_
 #define CC_TREES_LAYER_TREE_HOST_IMPL_H_
 
 #include <list>
 #include <set>
 #include <string>
@@ skipping 313 matching lines @@
   LayerImpl* InnerViewportScrollLayer() const;
   LayerImpl* OuterViewportScrollLayer() const;
   LayerImpl* CurrentlyScrollingLayer() const;
 
   int scroll_layer_id_when_mouse_over_scrollbar() const {
     return scroll_layer_id_when_mouse_over_scrollbar_;
   }
   bool scroll_affects_scroll_handler() const {
     return scroll_affects_scroll_handler_;
   }
+  void QueueSwapPromiseForMainThreadScrollUpdate(
+      scoped_ptr<SwapPromise> swap_promise);
 
   bool IsCurrentlyScrolling() const;
 
   virtual void SetVisible(bool visible);
   bool visible() const { return visible_; }
 
   void SetNeedsCommit() { client_->SetNeedsCommitOnImplThread(); }
   void SetNeedsRedraw();
 
   ManagedMemoryPolicy ActualManagedMemoryPolicy() const;
@@ skipping 224 matching lines @@
   void StartScrollbarFadeRecursive(LayerImpl* layer);
   void SetManagedMemoryPolicy(const ManagedMemoryPolicy& policy,
                               bool zero_budget);
   void EnforceManagedMemoryPolicy(const ManagedMemoryPolicy& policy);
 
   void DidInitializeVisibleTile();
 
   void MarkUIResourceNotEvicted(UIResourceId uid);
 
   void NotifySwapPromiseMonitorsOfSetNeedsRedraw();
+  void NotifySwapPromiseMonitorsOfForwardingToMainThread();
 
   typedef base::hash_map<UIResourceId, UIResourceData>
       UIResourceMap;
   UIResourceMap ui_resource_map_;
 
   // Resources that were evicted by EvictAllUIResources. Resources are removed
   // from this when they are touched by a create or destroy from the UI resource
   // request queue.
   std::set<UIResourceId> evicted_ui_resources_;
 
@@ skipping 26 matching lines @@
   // In impl-side painting mode, inert tree with layers that can be recycled
   // by the next sync from the main thread.
   scoped_ptr<LayerTreeImpl> recycle_tree_;
 
   InputHandlerClient* input_handler_client_;
   bool did_lock_scrolling_layer_;
   bool should_bubble_scrolls_;
   bool wheel_scrolling_;
   bool scroll_affects_scroll_handler_;
   int scroll_layer_id_when_mouse_over_scrollbar_;
+  ScopedPtrVector<SwapPromise> swap_promises_for_main_thread_scroll_update_;
 
   bool tile_priorities_dirty_;
 
   // The optional delegate for the root layer scroll offset.
   LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate_;
   LayerTreeSettings settings_;
   LayerTreeDebugState debug_state_;
   bool visible_;
   ManagedMemoryPolicy cached_managed_memory_policy_;
 
@@ skipping 83 matching lines @@
 
   std::vector<PictureLayerImpl*> picture_layers_;
   std::vector<PictureLayerImpl::Pair> picture_layer_pairs_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_