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

base/mac/mac_util.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 BASE_MAC_MAC_UTIL_H_
 #define BASE_MAC_MAC_UTIL_H_
-#pragma once
 
 #include <AvailabilityMacros.h>
 #include <Carbon/Carbon.h>
 #include <string>
 
 #include "base/base_export.h"
 #include "base/logging.h"
 
 // TODO(rohitrao): Clean up sites that include mac_util.h and remove this line.
 #include "base/mac/foundation_util.h"
@@ skipping 186 matching lines @@
 // If any error occurs, none of the input pointers are touched.
 BASE_EXPORT bool ParseModelIdentifier(const std::string& ident,
                                       std::string* type,
                                       int32* major,
                                       int32* minor);
 
 }  // namespace mac
 }  // namespace base
 
 #endif  // BASE_MAC_MAC_UTIL_H_