Use a direct include of strings headers, delete some strings forwarding headers.

remoting/client/plugin/pepper_signal_strategy.cc

 // Copyright 2013 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/client/plugin/pepper_signal_strategy.h"
 
-#include "base/string_number_conversions.h"
+#include "base/strings/string_number_conversions.h"
 #include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
 
 namespace remoting {
 
 PepperSignalStrategy::PepperSignalStrategy(
     std::string local_jid,
     const SendIqCallback& send_iq_callback)
     : local_jid_(local_jid),
       send_iq_callback_(send_iq_callback),
       last_id_(0) {
@@ skipping 47 matching lines @@
   send_iq_callback_.Run(stanza->Str());
   return true;
 }
 
 std::string PepperSignalStrategy::GetNextId() {
   ++last_id_;
   return base::IntToString(last_id_);
 }
 
 }  // namespace remoting