Remove #pragma once from ash

ash/accelerators/accelerator_dispatcher.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_ACCELERATORS_ACCELERATOR_DISPATCHER_H_
 #define ASH_ACCELERATORS_ACCELERATOR_DISPATCHER_H_
-#pragma once
 
 #include "ash/ash_export.h"
 #include "base/message_loop.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 
 namespace ash {
 
 // Dispatcher for handling accelerators in ash.
 // Wraps a nested dispatcher to which control is passed if no accelerator key
@@ skipping 20 matching lines @@
   // Window associated with |nested_dispatcher_| which is used to determine
   // whether the |nested_dispatcher_| is allowed to receive events.
   aura::Window* associated_window_;
 
   DISALLOW_COPY_AND_ASSIGN(AcceleratorDispatcher);
 };
 
 }  // namespace ash
 
 #endif  // ASH_ACCELERATORS_ACCELERATOR_DISPATCHER_H_