ui: Cleanup class/struct forward declarations

ui/views/widget/desktop_aura/desktop_cursor_loader_updater.h

 // Copyright (c) 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 UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_CURSOR_LOADER_UPDATER_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_CURSOR_LOADER_UPDATER_H_
 
 #include <memory>
 
 #include "ui/views/views_export.h"
 
-namespace aura {
-class RootWindow;
-}
-
 namespace display {
 class Display;
 }
 
 namespace ui {
 class CursorLoader;
 }
 
 namespace views {
 
@@ skipping 13 matching lines @@
 
   // Called when the display has changed (as we may need to reload the cursor
   // assets in response to a device scale factor or rotation change).
   virtual void OnDisplayUpdated(const display::Display& display,
                                 ui::CursorLoader* loader) = 0;
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_DISPLAY_CHANGE_HANDLER_H_