Use a direct include of strings headers in url/, win8/.

win8/metro_driver/file_picker.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 "stdafx.h"
 #include "win8/metro_driver/file_picker.h"
 
 #include <windows.storage.pickers.h>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/win/metro.h"
 #include "base/win/scoped_comptr.h"
 #include "win8/metro_driver/chrome_app_view.h"
 #include "win8/metro_driver/winrt_utils.h"
 
 namespace {
 
 namespace winstorage = ABI::Windows::Storage;
 typedef winfoundtn::Collections::IVector<HSTRING> StringVectorItf;
@@ skipping 586 matching lines @@
   OpenFilePickerSession session(open_file_name);
 
   return session.Run();
 }
 
 BOOL MetroGetSaveFileName(OPENFILENAME* open_file_name) {
   SaveFilePickerSession session(open_file_name);
 
   return session.Run();
 }