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

base/mac/launchd.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_LAUNCHD_H_
 #define BASE_MAC_LAUNCHD_H_
-#pragma once
 
 #include <launch.h>
 #include <sys/types.h>
 
 #include <string>
 
 #include "base/base_export.h"
 
 namespace base {
 namespace mac {
 
 // MessageForJob sends a single message to launchd with a simple dictionary
 // mapping |operation| to |job_label|, and returns the result of calling
 // launch_msg to send that message. On failure, returns NULL. The caller
 // assumes ownership of the returned launch_data_t object.
 BASE_EXPORT
 launch_data_t MessageForJob(const std::string& job_label,
                             const char* operation);
 
 // Returns the process ID for |job_label| if the job is running, 0 if the job
 // is loaded but not running, or -1 on error.
 BASE_EXPORT
 pid_t PIDForJob(const std::string& job_label);
 
 }  // namespace mac
 }  // namespace base
 
 #endif  // BASE_MAC_LAUNCHD_H_