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

base/memory/scoped_nsobject.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_SCOPED_NSOBJECT_H_
 #define BASE_MEMORY_SCOPED_NSOBJECT_H_
-#pragma once
 
 #import <Foundation/Foundation.h>
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_policy.h"
 
 // scoped_nsobject<> is patterned after scoped_ptr<>, but maintains ownership
 // of an NSObject subclass object.  Style deviations here are solely for
 // compatibility with scoped_ptr<>'s interface, with which everyone is already
 // familiar.
@@ skipping 143 matching lines @@
 // at top of header.
 template<>
 class scoped_nsobject<NSAutoreleasePool> {
  private:
   explicit scoped_nsobject(NSAutoreleasePool* object = nil,
                            base::scoped_policy::OwnershipPolicy policy =
                                base::scoped_policy::ASSUME);
   DISALLOW_COPY_AND_ASSIGN(scoped_nsobject);
 };
 #endif  // BASE_MEMORY_SCOPED_NSOBJECT_H_