Use a direct include of strings headers in chromeos/.

chromeos/dbus/fake_session_manager_client.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 "chromeos/dbus/fake_session_manager_client.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/message_loop.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "chromeos/dbus/cryptohome_client.h"
 
 namespace chromeos {
 
 FakeSessionManagerClient::FakeSessionManagerClient()
   : emit_login_prompt_ready_call_count_(0) ,
     notify_lock_screen_shown_call_count_(0),
     notify_lock_screen_dismissed_call_count_(0){
 }
 
@@ skipping 138 matching lines @@
     const std::string& account_id,
     const std::string& policy_blob) {
   device_local_account_policy_[account_id] = policy_blob;
 }
 
 void FakeSessionManagerClient::OnPropertyChangeComplete(bool success) {
   FOR_EACH_OBSERVER(Observer, observers_, PropertyChangeComplete(success));
 }
 
 }  // namespace chromeos