[Sync] Change std::wstring to string16 in SyncSetupFlowHandler.

chrome/browser/sync/sync_setup_flow_handler.h

 // Copyright (c) 2011 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_SYNC_SYNC_SETUP_FLOW_HANDLER_H_
 #define CHROME_BROWSER_SYNC_SYNC_SETUP_FLOW_HANDLER_H_
 #pragma once
 
 #include <string>
 
 class SyncSetupFlow;
 
 namespace base {
 class DictionaryValue;
 }
 
 class SyncSetupFlowHandler {
  public:
   // These functions control which part of the HTML is visible.
   virtual void ShowOAuthLogin() = 0;
   virtual void ShowGaiaLogin(const base::DictionaryValue& args) = 0;
   virtual void ShowGaiaSuccessAndClose() = 0;
   virtual void ShowGaiaSuccessAndSettingUp() = 0;
   virtual void ShowConfigure(const base::DictionaryValue& args) = 0;
   virtual void ShowPassphraseEntry(const base::DictionaryValue& args) = 0;
   virtual void ShowSettingUp() = 0;
-  virtual void ShowSetupDone(const std::wstring& user) = 0;
+  virtual void ShowSetupDone(const string16& user) = 0;
   virtual void SetFlow(SyncSetupFlow* flow) = 0;
   virtual void Focus() = 0;
 
  protected:
   virtual ~SyncSetupFlowHandler() {}
 };
 
 #endif  // CHROME_BROWSER_SYNC_SYNC_SETUP_FLOW_HANDLER_H_