Move ASCIIToWide and ASCIIToUTF16 to utf_string_conversions.h. I've found it...

net/http/http_auth_filter.h

 // Copyright (c) 2010 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 NET_HTTP_HTTP_AUTH_FILTER_H_
 #define NET_HTTP_HTTP_AUTH_FILTER_H_
 #pragma once
 
 #include <list>
 #include <set>
 #include <string>
 
-#include "base/string_util.h"
 #include "net/http/http_auth.h"
 #include "net/proxy/proxy_bypass_rules.h"
 
 class GURL;
 
 namespace net {
 
 // |HttpAuthFilter|s determine whether an authentication scheme should be
 // allowed for a particular peer.
 class HttpAuthFilter {
@@ skipping 34 matching lines @@
   // We are using ProxyBypassRules because they have the functionality that we
   // want, but we are not using it for proxy bypass.
   ProxyBypassRules rules_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpAuthFilterWhitelist);
 };
 
 }   // namespace net
 
 #endif  // NET_HTTP_HTTP_AUTH_FILTER_H_