Delay UpdateRect until the SwapBuffers callback when accelerated compositing is on.

content/browser/renderer_host/render_widget_helper.h

 // Copyright (c) 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 CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
 #pragma once
 
+#include <deque>
 #include <map>
 
 #include "base/atomic_sequence_num.h"
 #include "base/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/process.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "content/public/common/window_container_type.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupType.h"
@@ skipping 134 matching lines @@
   // Lookup the compositing surface corresponding to a widget ID.
   gfx::PluginWindowHandle LookupCompositingSurface(int render_widget_id);
 
  private:
   // A class used to proxy a paint message.  PaintMsgProxy objects are created
   // on the IO thread and destroyed on the UI thread.
   class UpdateMsgProxy;
   friend class UpdateMsgProxy;
   friend class base::RefCountedThreadSafe<RenderWidgetHelper>;
 
-  // Map from render_widget_id to live PaintMsgProxy instance.
-  typedef base::hash_map<int, UpdateMsgProxy*> UpdateMsgProxyMap;
+  typedef std::deque<UpdateMsgProxy*> UpdateMsgProxyQueue;
+  // Map from render_widget_id to a queue of live PaintMsgProxy instances.
+  typedef base::hash_map<int, UpdateMsgProxyQueue > UpdateMsgProxyMap;
 
   ~RenderWidgetHelper();
 
   // Called on the UI thread to discard a paint message.
   void OnDiscardUpdateMsg(UpdateMsgProxy* proxy);
 
   // Called on the UI thread to dispatch a paint message if necessary.
   void OnDispatchUpdateMsg(UpdateMsgProxy* proxy);
 
   // Called on the UI thread to finish creating a window.
@@ skipping 45 matching lines @@
 
   // The next routing id to use.
   base::AtomicSequenceNumber next_routing_id_;
 
   ResourceDispatcherHost* resource_dispatcher_host_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHelper);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_