Support browser side thumbnailing for GPU composited pages on Windows.

content/browser/renderer_host/render_widget_host_view_gtk.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_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #pragma once
 
 #include <gdk/gdk.h>
 
@@ skipping 54 matching lines @@
   virtual void Hide() OVERRIDE;
   virtual bool IsShowing() OVERRIDE;
   virtual gfx::Rect GetViewBounds() const OVERRIDE;
   virtual GdkEventButton* GetLastMouseDown() OVERRIDE;
 #if !defined(TOOLKIT_VIEWS)
   virtual gfx::NativeView BuildInputMethodsGtkMenu() OVERRIDE;
 #endif  // !defined(TOOLKIT_VIEWS)
   virtual void UnhandledWheelEvent(
       const WebKit::WebMouseWheelEvent& event) OVERRIDE;
   virtual void SetBackground(const SkBitmap& background) OVERRIDE;
+  virtual bool CopyFromCompositingSurface(
+      const gfx::Size& size,
+      skia::PlatformCanvas* output) OVERRIDE;
 
   // RenderWidgetHostViewPort implementation.
   virtual void InitAsPopup(content::RenderWidgetHostView* parent_host_view,
                            const gfx::Rect& pos) OVERRIDE;
   virtual void InitAsFullscreen(
       content::RenderWidgetHostView* reference_host_view) OVERRIDE;
   virtual void DidBecomeSelected() OVERRIDE;
   virtual void WasHidden() OVERRIDE;
   virtual void MovePluginWindows(
       const std::vector<webkit::npapi::WebPluginGeometry>& moves) OVERRIDE;
@@ skipping 208 matching lines @@
 
 #if defined(OS_CHROMEOS)
   // Custimized tooltip window.
   scoped_ptr<ui::TooltipWindowGtk> tooltip_window_;
 #endif  // defined(OS_CHROMEOS)
 
   ui::GtkSignalRegistrar signals_;
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_