Remove #pragma once from chromeos

chromeos/chromeos_switches.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 CHROMEOS_CHROMEOS_SWITCHES_H_
 #define CHROMEOS_CHROMEOS_SWITCHES_H_
-#pragma once
 
 #include "chromeos/chromeos_export.h"
 
 namespace chromeos {
 namespace switches {
 
 // Switches that are used in src/chromeos must go here.
 // Other switches that apply just to chromeos code should go here also (along
 // with any code that is specific to the chromeos system). ChromeOS specific UI
 // should be in src/ash.
 
 // Note: If you add a switch, consider if it needs to be copied to a subsequent
 // command line if the process executes a new copy of itself.  (For example,
 // see chromeos::LoginUtil::GetOffTheRecordCommandLine().)
 
 // Please keep alphabetized.
 CHROMEOS_EXPORT extern const char kDbusStub[];
 CHROMEOS_EXPORT extern const char kSmsTestMessages[];
 
 }  // namespace switches
 }  // namespace chromeos
 
 #endif  // CHROMEOS_CHROMEOS_SWITCHES_H_