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

win8/metro_driver/toast_notification_handler.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_METRO_DRIVER_TOAST_NOTIFICATION_HANDLER_H_
 #define CHROME_BROWSER_UI_METRO_DRIVER_TOAST_NOTIFICATION_HANDLER_H_
 
 #include <windows.ui.notifications.h>
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "base/win/metro.h"
 
 // Provides functionality to display a metro style toast notification.
 class ToastNotificationHandler {
  public:
   // Holds information about a desktop notification to be displayed.
   struct DesktopNotification {
     std::string origin_url;
     std::string icon_url;
     string16 title;
@@ skipping 25 matching lines @@
                      IInspectable* inspectable);
 
  private:
   mswr::ComPtr<winui::Notifications::IToastNotifier> notifier_;
   mswr::ComPtr<winui::Notifications::IToastNotification> notification_;
   EventRegistrationToken activated_token_;
   DesktopNotification notification_info_;
 };
 
 #endif  // CHROME_BROWSER_UI_METRO_DRIVER_TOAST_NOTIFICATION_HANDLER_H_