Introduce XGetImage() for GrabWindowSnapshot() in ChromeOS.

ui/aura/root_window.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 UI_AURA_ROOT_WINDOW_H_
 #define UI_AURA_ROOT_WINDOW_H_
 #pragma once
 
+#include <vector>
+
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/focus_manager.h"
 #include "ui/aura/window.h"
 #include "ui/base/cursor/cursor.h"
 #include "ui/base/events.h"
@@ skipping 215 matching lines @@
   // release before we resume normal operation.
   void HoldMouseMoves();
   void ReleaseMouseMoves();
 
   // Creates a compositor lock.
   scoped_refptr<CompositorLock> GetCompositorLock();
 
   // Sets if the window should be focused when shown.
   void SetFocusWhenShown(bool focus_when_shown);
 
+  // Grabs the snapshot of the root window by using the platform-dependent APIs.
+  bool GrabSnapshot(const gfx::Rect& snapshot_bounds,
+                    std::vector<unsigned char>* png_representation);
+
   // Overridden from Window:
   virtual RootWindow* GetRootWindow() OVERRIDE;
   virtual const RootWindow* GetRootWindow() const OVERRIDE;
   virtual void SetTransform(const ui::Transform& transform) OVERRIDE;
 
   // Overridden from ui::CompositorDelegate:
   virtual void ScheduleDraw() OVERRIDE;
 
   // Overridden from ui::CompositorObserver:
   virtual void OnCompositingStarted(ui::Compositor*) OVERRIDE;
@@ skipping 143 matching lines @@
   bool draw_on_compositor_unlock_;
 
   int draw_trace_count_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindow);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_ROOT_WINDOW_H_