Remove #pragma once. Just from base/ for now.

base/test/mock_chrome_application_mac.h

 // Copyright (c) 2011 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 BASE_TEST_MOCK_CHROME_APPLICATION_MAC_H_
 #define BASE_TEST_MOCK_CHROME_APPLICATION_MAC_H_
-#pragma once
 
 #if defined(__OBJC__)
 
 #import <AppKit/AppKit.h>
 
 #include "base/mac/scoped_sending_event.h"
 #include "base/message_pump_mac.h"
 
 // A basic implementation of CrAppProtocol and
 // CrAppControlProtocol. This can be used in tests that need an
 // NSApplication and use a runloop, or which need a ScopedSendingEvent
 // when handling a nested event loop.
 @interface MockCrApp : NSApplication<CrAppProtocol,
                                      CrAppControlProtocol> {
  @private
   BOOL handlingSendEvent_;
 }
 @end
 
 #endif
 
 // To be used to instantiate MockCrApp from C++ code.
 namespace mock_cr_app {
 void RegisterMockCrApp();
 }  // namespace mock_cr_app
 
 #endif  // BASE_TEST_MOCK_CHROME_APPLICATION_MAC_H_