ui/gfx: Make gfx::Canvas inherit from gfx::CanvasSkia.

chrome/browser/ui/views/tabs/native_view_photobooth.h

-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// 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 CHROME_BROWSER_UI_VIEWS_TABS_NATIVE_VIEW_PHOTOBOOTH_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_NATIVE_VIEW_PHOTOBOOTH_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
-class Canvas;
+class CanvasSkia;
 class Rect;
 }
 ///////////////////////////////////////////////////////////////////////////////
 // NativeViewPhotobooth
 //
 //  An object that a NativeView "steps into" to have its picture taken. This is
 //  used to generate a full size screen shot of the contents of a NativeView
 //  including any child windows.
 //
 //  Implementation note: This causes the NativeView to be re-parented to a
 //  mostly off-screen layered window.
 //
 class NativeViewPhotobooth {
  public:
   // Creates the photo booth. Constructs a nearly off-screen window, parents
   // the view, then shows it. The caller is responsible for destroying this
   // photo-booth, since the photo-booth will detach it before it is destroyed.
   static NativeViewPhotobooth* Create(gfx::NativeView initial_view);
 
   // Destroys the photo booth window.
   virtual ~NativeViewPhotobooth() {}
 
   // Replaces the view in the photo booth with the specified one.
   virtual void Replace(gfx::NativeView new_view) = 0;
 
   // Paints the current display image of the window into |canvas|, clipped to
   // |target_bounds|.
-  virtual void PaintScreenshotIntoCanvas(gfx::Canvas* canvas,
+  virtual void PaintScreenshotIntoCanvas(gfx::CanvasSkia* canvas,
                                          const gfx::Rect& target_bounds) = 0;
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_NATIVE_VIEW_PHOTOBOOTH_H_