Remove #pragma once from content

content/public/common/zygote_fork_delegate_linux.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 CONTENT_PUBLIC_COMMON_ZYGOTE_FORK_DELEGATE_LINUX_H_
 #define CONTENT_PUBLIC_COMMON_ZYGOTE_FORK_DELEGATE_LINUX_H_
-#pragma once
 
 #include <unistd.h>
 
 #include <string>
 #include <vector>
 
 namespace content {
 
 // The ZygoteForkDelegate allows the Chrome Linux zygote to delegate
 // fork operations to another class that knows how to do some
@@ skipping 32 matching lines @@
 
   // After a successful for, signal the child to indicate that
   // the child's PID has been received. Also communicate the
   // channel switch as a part of acknowledgement message.
   virtual bool AckChild(int fd, const std::string& channel_switch) = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_ZYGOTE_FORK_DELEGATE_LINUX_H_