Fix race conditions in window snapshot code.

content/renderer/render_widget.h

 // Copyright (c) 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 CONTENT_RENDERER_RENDER_WIDGET_H_
 #define CONTENT_RENDERER_RENDER_WIDGET_H_
 
 #include <deque>
 #include <map>
 
@@ skipping 223 matching lines @@
   // Emulates screen and widget metrics. Supplied values override everything
   // coming from host.
   void EnableScreenMetricsEmulation(
       const gfx::Size& device_size,
       const gfx::Rect& widget_rect,
       float device_scale_factor,
       bool fit_to_view);
   void DisableScreenMetricsEmulation();
   void SetPopupOriginAdjustmentsForEmulation(ScreenMetricsEmulator* emulator);
 
+  void ScheduleCompositeWithForcedRedraw();
+
  protected:
   // Friend RefCounted so that the dtor can be non-public. Using this class
   // without ref-counting is an error.
   friend class base::RefCounted<RenderWidget>;
   // For unit tests.
   friend class RenderWidgetTest;
 
   enum ResizeAck {
     SEND_RESIZE_ACK,
     NO_RESIZE_ACK,
@@ skipping 286 matching lines @@
 
   // Check whether the WebWidget has any touch event handlers registered.
   virtual void hasTouchEventHandlers(bool has_handlers);
 
   // Creates a 3D context associated with this view.
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> CreateGraphicsContext3D(
       const WebKit::WebGraphicsContext3D::Attributes& attributes);
 
   bool OnSnapshotHelper(const gfx::Rect& src_subrect, SkBitmap* bitmap);
 
+  void ScheduleCompositeImpl(bool force_redraw);
+
   // Routing ID that allows us to communicate to the parent browser process
   // RenderWidgetHost. When MSG_ROUTING_NONE, no messages may be sent.
   int32 routing_id_;
 
   int32 surface_id_;
 
   // We are responsible for destroying this object via its Close method.
   WebKit::WebWidget* webwidget_;
 
   // This is lazily constructed and must not outlive webwidget_.
@@ skipping 222 matching lines @@
   float popup_origin_scale_for_emulation_;
 
   base::WeakPtrFactory<RenderWidget> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_