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

ui/views/controls/menu/menu_scroll_view_container.h

-// Copyright (c) 2011 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 UI_VIEWS_CONTROLS_MENU_MENU_SCROLL_VIEW_CONTAINER_H_
 #define UI_VIEWS_CONTROLS_MENU_MENU_SCROLL_VIEW_CONTAINER_H_
 #pragma once
 
 #include "ui/views/view.h"
 
 namespace views {
 
 class SubmenuView;
 
 // MenuScrollViewContainer contains the SubmenuView (through a MenuScrollView)
 // and two scroll buttons. The scroll buttons are only visible and enabled if
 // the preferred height of the SubmenuView is bigger than our bounds.
 class MenuScrollViewContainer : public View {
  public:
   explicit MenuScrollViewContainer(SubmenuView* content_view);
 
   // Returns the buttons for scrolling up/down.
   View* scroll_down_button() const { return scroll_down_button_; }
   View* scroll_up_button() const { return scroll_up_button_; }
 
   // View overrides.
-  virtual void OnPaintBackground(gfx::Canvas* canvas) OVERRIDE;
+  virtual void OnPaintBackground(gfx::CanvasSkia* canvas) OVERRIDE;
   virtual void Layout() OVERRIDE;
   virtual gfx::Size GetPreferredSize() OVERRIDE;
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
 
  protected:
   // View override.
   virtual void OnBoundsChanged(const gfx::Rect& previous_bounds) OVERRIDE;
 
  private:
   class MenuScrollView;
 
   // The scroll buttons.
   View* scroll_up_button_;
   View* scroll_down_button_;
 
   // The scroll view.
   MenuScrollView* scroll_view_;
 
   // The content view.
   SubmenuView* content_view_;
 
   DISALLOW_COPY_AND_ASSIGN(MenuScrollViewContainer);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_MENU_MENU_SCROLL_VIEW_CONTAINER_H_