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

base/memory/ref_counted.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_MEMORY_REF_COUNTED_H_
 #define BASE_MEMORY_REF_COUNTED_H_
-#pragma once
 
 #include <cassert>
 
 #include "base/atomic_ref_count.h"
 #include "base/base_export.h"
 #include "base/threading/thread_collision_warner.h"
 
 namespace base {
 
 namespace subtle {
@@ skipping 288 matching lines @@
 };
 
 // Handy utility for creating a scoped_refptr<T> out of a T* explicitly without
 // having to retype all the template arguments
 template <typename T>
 scoped_refptr<T> make_scoped_refptr(T* t) {
   return scoped_refptr<T>(t);
 }
 
 #endif  // BASE_MEMORY_REF_COUNTED_H_