Makes native_widget_types forward declare ui::Cursor.

ash/wm/image_cursors.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 ASH_WM_IMAGE_CURSORS_H_
 #define ASH_WM_IMAGE_CURSORS_H_
 
 #include "ash/ash_export.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
+#include "ui/base/cursor/cursor.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 class Display;
 }
 
 namespace ui {
 class CursorLoader;
 }
 
@@ skipping 32 matching lines @@
   scoped_ptr<ui::CursorLoader> cursor_loader_;
   float scale_;
   ui::CursorSetType cursor_set_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageCursors);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_IMAGE_CURSORS_H_