ash: Cleanup class/struct forward declarations

ash/display/resolution_notification_controller.h

 // Copyright 2013 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_RESOLUTION_NOTIFICATION_CONTROLLER_H_
 #define ASH_DISPLAY_RESOLUTION_NOTIFICATION_CONTROLLER_H_
 
 #include <stdint.h>
 
 #include "ash/ash_export.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "ui/display/display_observer.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace chromeos {
 FORWARD_DECLARE_TEST(DisplayPreferencesTest, PreventStore);
 }  // namespace chromeos
 
-namespace views {
-class Label;
-class Widget;
-}  // namespace views
-
 namespace ash {
 
-class DisplayMode;
-
 // A class which manages the notification of display resolution change and
 // also manages the timeout in case the new resolution is unusable.
 class ASH_EXPORT ResolutionNotificationController
     : public display::DisplayObserver,
       public WindowTreeHostManager::Observer {
  public:
   ResolutionNotificationController();
   ~ResolutionNotificationController() override;
 
   // Prepare a resolution change notification for |display_id| from
@@ skipping 59 matching lines @@
   static void SuppressTimerForTest();
 
   std::unique_ptr<ResolutionChangeInfo> change_info_;
 
   DISALLOW_COPY_AND_ASSIGN(ResolutionNotificationController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_RESOLUTION_NOTIFICATION_CONTROLLER_H_