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

ash/status_area/status_area_view.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 ASH_STATUS_AREA_STATUS_AREA_VIEW_H_
 #define ASH_STATUS_AREA_STATUS_AREA_VIEW_H_
 #pragma once
 
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/views/accessible_pane_view.h"
 #include "ui/views/widget/widget_delegate.h"
 
 namespace ash {
 namespace internal {
 
 class StatusAreaView : public views::WidgetDelegate,
                        public views::AccessiblePaneView {
  public:
   StatusAreaView();
   virtual ~StatusAreaView();
 
   // Overridden from views::View:
   virtual gfx::Size GetPreferredSize() OVERRIDE;
   virtual views::Widget* GetWidget() OVERRIDE;
   virtual const views::Widget* GetWidget() const OVERRIDE;
 
  private:
-  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
+  virtual void OnPaint(gfx::CanvasSkia* canvas) OVERRIDE;
 
   SkBitmap status_mock_;
 
   DISALLOW_COPY_AND_ASSIGN(StatusAreaView);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_STATUS_AREA_STATUS_AREA_VIEW_H_