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

ui/base/dragdrop/drag_utils.h

 // Copyright (c) 2011 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_BASE_DRAGDROP_DRAG_UTILS_H_
 #define UI_BASE_DRAGDROP_DRAG_UTILS_H_
 #pragma once
 
 #include <string>
 
 #include "base/file_path.h"
 #include "ui/base/ui_export.h"
 
 class GURL;
 class SkBitmap;
 
 namespace gfx {
-class Canvas;
+class CanvasSkia;

[Ben Goodger (Google), 2012/03/06 15:46:58]

????

 class Point;
 class Size;
 }
 
 namespace ui {
 class OSExchangeData;
 }
 using ui::OSExchangeData;
 
 namespace drag_utils {
 
 // Creates a dragging image to be displayed when the user drags a file from
 // Chrome (via the download manager, for example). The drag image is set into
 // the supplied data_object. 'file_name' can be a full path, but the directory
 // portion will be truncated in the drag image.
 UI_EXPORT void CreateDragImageForFile(const FilePath& file_name,
                                       const SkBitmap* icon,
                                       ui::OSExchangeData* data_object);
 
 // Sets the drag image on data_object from the supplied canvas. width/height
 // are the size of the image to use, and the offsets give the location of
 // the hotspot for the drag image.
-UI_EXPORT void SetDragImageOnDataObject(const gfx::Canvas& canvas,
+UI_EXPORT void SetDragImageOnDataObject(const gfx::CanvasSkia& canvas,
                                         const gfx::Size& size,
                                         const gfx::Point& cursor_offset,
                                         ui::OSExchangeData* data_object);
 
 // Sets the drag image on data_object from the supplied bitmap. width/height
 // are the size of the image to use, and the offsets give the location of
 // the hotspot for the drag image.
 UI_EXPORT void SetDragImageOnDataObject(const SkBitmap& bitmap,
                                         const gfx::Size& size,
                                         const gfx::Point& cursor_offset,
                                         ui::OSExchangeData* data_object);
 
 }  // namespace drag_utils
 
 #endif  // UI_BASE_DRAGDROP_DRAG_UTILS_H_