Remove #pragma once from ash

ash/wm/event_client_impl.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_EVENT_CLIENT_IMPL_H_
 #define ASH_WM_EVENT_CLIENT_IMPL_H_
-#pragma once
 
 #include "ash/ash_export.h"
 #include "ui/aura/client/event_client.h"
 
 namespace aura {
 class RootWindow;
 }
 
 namespace ash {
 namespace internal {
@@ skipping 10 matching lines @@
 
   aura::RootWindow* root_window_;
 
   DISALLOW_COPY_AND_ASSIGN(EventClientImpl);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_EVENT_CLIENT_IMPL_H_