cc: Delay start of scrollbar animation setNeedsRedraw.

cc/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_LAYER_TREE_HOST_IMPL_H_
 #define CC_LAYER_TREE_HOST_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
@@ skipping 47 matching lines @@
       scoped_ptr<AnimationEventsVector> events,
       base::Time wall_clock_time) = 0;
   // Returns true if resources were deleted by this call.
   virtual bool ReduceContentsTextureMemoryOnImplThread(
       size_t limit_bytes,
       int priority_cutoff) = 0;
   virtual void ReduceWastedContentsTextureMemoryOnImplThread() = 0;
   virtual void SendManagedMemoryStats() = 0;
   virtual bool IsInsideDraw() = 0;
   virtual void RenewTreePriority() = 0;
+  virtual void RequestScrollbarAnimationOnImplThread(double delay) = 0;

[jamesr, 2013/03/14 19:52:01]

let's use base::TimeDeltas for delays.  With this signature I'm not sure what
unit the delay is supposed to be in

 };
 
 // LayerTreeHostImpl owns the LayerImpl trees as well as associated rendering
 // state.
 class CC_EXPORT LayerTreeHostImpl : public InputHandlerClient,
                                     public RendererClient,
                                     public TileManagerClient,
                                     public OutputSurfaceClient,
                                     public TopControlsManagerClient {
   typedef std::vector<LayerImpl*> LayerList;
@@ skipping 23 matching lines @@
                                        base::TimeDelta duration) OVERRIDE;
   virtual void ScheduleAnimation() OVERRIDE;
   virtual bool HaveTouchEventHandlersAt(gfx::Point viewport_port) OVERRIDE;
 
   // TopControlsManagerClient implementation.
   virtual void setActiveTreeNeedsUpdateDrawProperties() OVERRIDE;
   virtual void setNeedsRedraw() OVERRIDE;
   virtual bool haveRootScrollLayer() const OVERRIDE;
   virtual float rootScrollLayerTotalScrollY() const OVERRIDE;
 
+  void StartScrollbarAnimation(base::TimeTicks now);
+
   struct CC_EXPORT FrameData : public RenderPassSink {
     FrameData();
     ~FrameData();
 
     std::vector<gfx::Rect> occluding_screen_space_rects;
     std::vector<gfx::Rect> non_occluding_screen_space_rects;
     RenderPassList render_passes;
     RenderPassIdHashMap render_passes_by_id;
     const LayerList* render_surface_layer_list;
     LayerList will_draw_layers;
@@ skipping 249 matching lines @@
 
   void AnimateScrollbarsRecursive(LayerImpl* layer,
                                   base::TimeTicks time);
 
   void DumpRenderSurfaces(std::string* str,
                           int indent,
                           const LayerImpl* layer) const;
 
   static LayerImpl* GetNonCompositedContentLayerRecursive(LayerImpl* layer);
 
+  void StartScrollbarAnimationRecursive(LayerImpl* layer, base::TimeTicks time);
+
   scoped_ptr<OutputSurface> output_surface_;
   scoped_ptr<ResourceProvider> resource_provider_;
   scoped_ptr<Renderer> renderer_;
   scoped_ptr<TileManager> tile_manager_;
 
   // Tree currently being drawn.
   scoped_ptr<LayerTreeImpl> active_tree_;
 
   // In impl-side painting mode, tree with possibly incomplete rasterized
   // content. May be promoted to active by ActivatePendingTreeIfNeeded().
@@ skipping 47 matching lines @@
   base::TimeTicks current_frame_time_;
 
   scoped_ptr<AnimationRegistrar> animation_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_IMPL_H_