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

ui/views/controls/scrollbar/base_scroll_bar.h

Index: ui/views/controls/scrollbar/base_scroll_bar.h
diff --git a/ui/views/controls/scrollbar/base_scroll_bar.h b/ui/views/controls/scrollbar/base_scroll_bar.h
index 46515d5c14347d704ab827ce8190e62d1293bad6..69714581862b8a8ab69a879d31e9a94cfa5f5736 100644
--- a/ui/views/controls/scrollbar/base_scroll_bar.h
+++ b/ui/views/controls/scrollbar/base_scroll_bar.h
@@ -1,4 +1,4 @@
-// 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.
 
@@ -84,7 +84,7 @@ class VIEWS_EXPORT BaseScrollBar : public ScrollBar,
 
  protected:
   // View overrides:
-  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE = 0;
+  virtual void OnPaint(gfx::CanvasSkia* canvas) OVERRIDE = 0;
 
   BaseScrollBarThumb* GetThumb() const;