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

ui/views/controls/button/menu_button.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_BUTTON_MENU_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_MENU_BUTTON_H_
 #pragma once
 
 #include <string>
 
 #include "base/string16.h"
@@ skipping 30 matching lines @@
     menu_marker_ = menu_marker;
   }
 
   const gfx::Point& menu_offset() const { return menu_offset_; }
   void set_menu_offset(int x, int y) { menu_offset_.SetPoint(x, y); }
 
   // Activate the button (called when the button is pressed).
   virtual bool Activate();
 
   // Overridden from TextButton for the potential use of a drop marker.
-  virtual void PaintButton(gfx::Canvas* canvas, PaintButtonMode mode) OVERRIDE;
+  virtual void PaintButton(gfx::CanvasSkia* canvas,
+                           PaintButtonMode mode) OVERRIDE;
 
   // Overridden from View:
   virtual gfx::Size GetPreferredSize() OVERRIDE;
   virtual std::string GetClassName() const OVERRIDE;
   virtual bool OnMousePressed(const MouseEvent& event) OVERRIDE;
   virtual void OnMouseReleased(const MouseEvent& event) OVERRIDE;
   virtual void OnMouseExited(const MouseEvent& event) OVERRIDE;
   virtual bool OnKeyPressed(const KeyEvent& event) OVERRIDE;
   virtual bool OnKeyReleased(const KeyEvent& event) OVERRIDE;
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
@@ skipping 33 matching lines @@
   // If non-null the destuctor sets this to true. This is set while the menu is
   // showing and used to detect if the menu was deleted while running.
   bool* destroyed_flag_;
 
   DISALLOW_COPY_AND_ASSIGN(MenuButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_MENU_BUTTON_H_