"Buttery Smooth" Tab Capture.

content/browser/compositor/delegated_frame_host.h

 // Copyright 2014 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 CONTENT_BROWSER_COMPOSITOR_DELEGATED_FRAME_HOST_H_
 #define CONTENT_BROWSER_COMPOSITOR_DELEGATED_FRAME_HOST_H_
 
 #include "cc/layers/delegated_frame_provider.h"
 #include "cc/layers/delegated_frame_resource_collection.h"
 #include "cc/output/copy_output_result.h"
@@ skipping 194 matching lines @@
 
   void SendDelegatedFrameAck(uint32 output_surface_id);
   void SendReturnedDelegatedResources(uint32 output_surface_id);
 
   // DelegatedFrameEvictorClient implementation.
   virtual void EvictDelegatedFrame() OVERRIDE;
 
   // cc::DelegatedFrameProviderClient implementation.
   virtual void UnusedResourcesAreAvailable() OVERRIDE;
 
-  void DidReceiveFrameFromRenderer();
+  void DidReceiveFrameFromRenderer(const gfx::Rect& damage_rect);
 
   DelegatedFrameHostClient* client_;
 
   std::vector<base::Closure> on_compositing_did_commit_callbacks_;
 
   // The vsync manager we are observing for changes, if any.
   scoped_refptr<ui::CompositorVSyncManager> vsync_manager_;
 
+  // The current VSync timebase and interval. These are zero until the first
+  // call to OnUpdateVSyncParameters().
+  base::TimeTicks vsync_timebase_;
+  base::TimeDelta vsync_interval_;
+
   // With delegated renderer, this is the last output surface, used to
   // disambiguate resources with the same id coming from different output
   // surfaces.
   uint32 last_output_surface_id_;
 
   // The number of delegated frame acks that are pending, to delay resource
   // returns until the acks are sent.
   int pending_delegated_ack_count_;
 
   // True after a delegated frame has been skipped, until a frame is not
@@ skipping 43 matching lines @@
   // YUV readback pipeline.
   scoped_ptr<content::ReadbackYUVInterface>
       yuv_readback_pipeline_;
 
   scoped_ptr<DelegatedFrameEvictor> delegated_frame_evictor_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_COMPOSITOR_DELEGATED_FRAME_HOST_H_