ash: Cleanup class/struct forward declarations

ash/display/unified_mouse_warp_controller.h

 // Copyright 2015 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_DISPLAY_UNIFIED_MOUSE_WARP_CONTROLLER_H_
 #define ASH_DISPLAY_UNIFIED_MOUSE_WARP_CONTROLLER_H_
 
 #include "ash/display/mouse_warp_controller.h"
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "ui/gfx/geometry/rect.h"
 
-namespace aura {
-class Window;
-}
-
 namespace gfx {
 class Point;
 }
 
 namespace ash {
 namespace test {
 class AshTestBase;
 class DisplayManagerTestApi;
 }
 
@@ skipping 31 matching lines @@
   int64_t current_cursor_display_id_;
 
   bool update_location_for_test_;
 
   DISALLOW_COPY_AND_ASSIGN(UnifiedMouseWarpController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_UNIFIED_MOUSE_WARP_CONTROLLER_H_