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

base/values.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.
 
 // This file specifies a recursive data storage class called Value intended for
 // storing setting and other persistable data.  It includes the ability to
 // specify (recursive) lists and dictionaries, so it's fairly expressive.
 // However, the API is optimized for the common case, namely storing a
 // hierarchical tree of simple values.  Given a DictionaryValue root, you can
 // easily do things like:
 //
 // root->SetString("global.pages.homepage", "http://goateleporter.com");
 // std::string homepage = "http://google.com";  // default/fallback value
 // root->GetString("global.pages.homepage", &homepage);
 //
 // where "global" and "pages" are also DictionaryValues, and "homepage" is a
 // string setting.  If some elements of the path didn't exist yet, the
 // SetString() method would create the missing elements and attach them to root
 // before attaching the homepage value.
 
 #ifndef BASE_VALUES_H_
 #define BASE_VALUES_H_
-#pragma once
 
 #include <iterator>
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/string16.h"
@@ skipping 459 matching lines @@
 
 }  // namespace base
 
 // http://crbug.com/88666
 using base::DictionaryValue;
 using base::ListValue;
 using base::StringValue;
 using base::Value;
 
 #endif  // BASE_VALUES_H_