Use a direct include of strings headers in chromeos/.

chromeos/network/network_profile_handler.cc

 // Copyright (c) 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/network/network_profile_handler.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/values.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/shill_manager_client.h"
 #include "chromeos/dbus/shill_profile_client.h"
 #include "chromeos/network/network_profile_observer.h"
 #include "dbus/object_path.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
 
 namespace chromeos {
 
@@ skipping 168 matching lines @@
       base::Bind(&NetworkProfileHandler::GetManagerPropertiesCallback,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 NetworkProfileHandler::~NetworkProfileHandler() {
   DBusThreadManager::Get()->GetShillManagerClient()->
       RemovePropertyChangedObserver(this);
 }
 
 }  // namespace chromeos