Add base:: to string16s in win8/.

win8/metro_driver/metro_dialog_box.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 "win8/metro_driver/stdafx.h"
 
 #include "win8/metro_driver/chrome_app_view.h"
 #include "win8/metro_driver/metro_dialog_box.h"
 #include "win8/metro_driver/winrt_utils.h"
 
@@ skipping 123 matching lines @@
     PostMessage(dialog_box, WM_CLOSE, 0, 0);
 }
 
 HRESULT STDMETHODCALLTYPE MetroDialogBox::Invoke(
     winui::Popups::IUICommand* command) {
   DVLOG(1) << __FUNCTION__;
 
   mswrw::HString label;
   command->get_Label(label.GetAddressOf());
 
-  string16 button_label = MakeStdWString(label.Get());
+  base::string16 button_label = MakeStdWString(label.Get());
   DVLOG(1) << "Clicked button label is : " << button_label;
   if (button_label == dialog_box_info_.button1_label) {
     DVLOG(1) << "Button1 clicked";
     DCHECK(dialog_box_info_.button1_handler);
     dialog_box_info_.button1_handler();
   } else if (button_label == dialog_box_info_.button2_label) {
     DVLOG(1) << "Button2 clicked";
     DCHECK(dialog_box_info_.button2_handler);
     dialog_box_info_.button2_handler();
   }
   // The dialog box is destroyed once we return from invoke. Go ahead and
   // dismiss it.
   Dismiss();
   return S_OK;
 }