Use a direct include of strings headers in remoting/.

remoting/protocol/me2me_host_authenticator_factory.cc

 // 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.
 
 #include "remoting/protocol/me2me_host_authenticator_factory.h"
 
 #include "base/base64.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "remoting/base/rsa_key_pair.h"
 #include "remoting/protocol/channel_authenticator.h"
 #include "remoting/protocol/negotiating_host_authenticator.h"
 #include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
 
 namespace remoting {
 namespace protocol {
 
 namespace {
 
@@ skipping 115 matching lines @@
     return NegotiatingHostAuthenticator::CreateWithSharedSecret(
         local_cert_, key_pair_, shared_secret_hash_.value,
         shared_secret_hash_.hash_function, pairing_registry_);
   }
 
   return scoped_ptr<Authenticator>(new RejectingAuthenticator());
 }
 
 }  // namespace protocol
 }  // namespace remoting