ui: Remove SkCanvas methods from drag utils.

ui/views/drag_utils.h

 // 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_DRAG_UTILS_H_
 #define UI_VIEWS_DRAG_UTILS_H_
 
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/views_export.h"
 
 namespace gfx {
-class Canvas;
 class Point;
-class Size;
 }
 
 namespace ui {
 class OSExchangeData;
 }
 
 namespace views {
 class Widget;
 
 // Starts a drag operation. This blocks until the drag operation completes.
 VIEWS_EXPORT void RunShellDrag(gfx::NativeView view,
                                const ui::OSExchangeData& data,
                                const gfx::Point& location,
                                int operation,
                                ui::DragDropTypes::DragEventSource source);
 
 // Returns the device scale for the display associated with this |widget|'s
 // native view.
 VIEWS_EXPORT float ScaleFactorForDragFromWidget(const Widget* widget);
 
-// Returns a canvas that can be used to draw the drag image. Caller owns the
-// returned object. |widget| is Widget hosting the view being dragged.
-VIEWS_EXPORT gfx::Canvas* GetCanvasForDragImage(const Widget* widget,
-                                                const gfx::Size& canvas_size);
-
 }  // namespace views
 
 #endif  // UI_VIEWS_DRAG_UTILS_H_