ui: Cleanup class/struct forward declarations

ui/base/dragdrop/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_BASE_DRAGDROP_DRAG_UTILS_H_
 #define UI_BASE_DRAGDROP_DRAG_UTILS_H_
 
 #include <string>
 
 #include "base/files/file_path.h"
 #include "ui/base/ui_base_export.h"
 
-class GURL;
-
 namespace gfx {
 class Canvas;
 class ImageSkia;
-class Size;
 class Vector2d;
 }
 
 namespace ui {
 class OSExchangeData;
 }
 using ui::OSExchangeData;
 
 namespace drag_utils {
 
@@ skipping 13 matching lines @@
 
 // Sets the drag image on data_object from the supplied ImageSkia.
 // |cursor_offset| gives the location of the hotspot for the drag image.
 UI_BASE_EXPORT void SetDragImageOnDataObject(const gfx::ImageSkia& image_skia,
                                              const gfx::Vector2d& cursor_offset,
                                              ui::OSExchangeData* data_object);
 
 }  // namespace drag_utils
 
 #endif  // UI_BASE_DRAGDROP_DRAG_UTILS_H_