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

ui/views/controls/button/image_button.cc

-// 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.
 
 #include "ui/views/controls/button/image_button.h"
 
 #include "base/utf_string_conversions.h"
 #include "ui/base/animation/throb_animation.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/skbitmap_operations.h"
 
@@ skipping 45 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // ImageButton, View overrides:
 
 gfx::Size ImageButton::GetPreferredSize() {
   if (!images_[BS_NORMAL].isNull())
     return gfx::Size(images_[BS_NORMAL].width(), images_[BS_NORMAL].height());
   return preferred_size_;
 }
 
-void ImageButton::OnPaint(gfx::Canvas* canvas) {
+void ImageButton::OnPaint(gfx::CanvasSkia* canvas) {
   // Call the base class first to paint any background/borders.
   View::OnPaint(canvas);
 
   SkBitmap img = GetImageToPaint();
 
   if (!img.isNull()) {
     int x = 0, y = 0;
 
     if (h_alignment_ == ALIGN_CENTER)
       x = (width() - img.width()) / 2;
@@ skipping 87 matching lines @@
 bool ToggleImageButton::GetTooltipText(const gfx::Point& p,
                                        string16* tooltip) const {
   if (!toggled_ || toggled_tooltip_text_.empty())
     return Button::GetTooltipText(p, tooltip);
 
   *tooltip = toggled_tooltip_text_;
   return true;
 }
 
 }  // namespace views