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

base/process.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_PROCESS_H_
 #define BASE_PROCESS_H_
-#pragma once
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "build/build_config.h"
 
 #include <sys/types.h>
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
@@ skipping 65 matching lines @@
   // of this value is OS dependent.
   int GetPriority() const;
 
  private:
   ProcessHandle process_;
 };
 
 }  // namespace base
 
 #endif  // BASE_PROCESS_H_