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

base/file_version_info_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_FILE_VERSION_INFO_MAC_H_
 #define BASE_FILE_VERSION_INFO_MAC_H_
-#pragma once
 
 #include <string>
 
 #include "base/file_version_info.h"
 #include "base/memory/scoped_nsobject.h"
 
 #ifdef __OBJC__
 @class NSBundle;
 #else
 class NSBundle;
@@ skipping 27 matching lines @@
   // Returns a string16 value for a property name.
   // Returns the empty string if the property does not exist.
   string16 GetString16Value(CFStringRef name);
 
   scoped_nsobject<NSBundle> bundle_;
 
   DISALLOW_COPY_AND_ASSIGN(FileVersionInfoMac);
 };
 
 #endif  // BASE_FILE_VERSION_INFO_MAC_H_