Make using WebContentsUserData simpler.

chrome/browser/ui/sync/one_click_signin_helper.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_SYNC_ONE_CLICK_SIGNIN_HELPER_H_
 #define CHROME_BROWSER_UI_SYNC_ONE_CLICK_SIGNIN_HELPER_H_
 
 #include <string>
 
 #include "chrome/browser/common/web_contents_user_data.h"
@@ skipping 32 matching lines @@
 
   // Looks for the Google-Accounts-SignIn response header, and if found,
   // tries to display an infobar in the tab contents identified by the
   // child/route id.
   static void ShowInfoBarIfPossible(net::URLRequest* request,
                                     int child_id,
                                     int route_id);
 
  private:
   explicit OneClickSigninHelper(content::WebContents* web_contents);
-  static int kUserDataKey;
   friend class WebContentsUserData<OneClickSigninHelper>;
 
   // The portion of ShowInfoBarIfPossible() that needs to run on the UI thread.
   static void ShowInfoBarUIThread(const std::string& session_index,
                                   const std::string& email,
                                   int child_id,
                                   int route_id);
 
   // content::WebContentsObserver overrides.
   virtual void DidNavigateAnyFrame(
@@ skipping 11 matching lines @@
 
   // Information about the account that has just logged in.
   std::string session_index_;
   std::string email_;
   std::string password_;
 
   DISALLOW_COPY_AND_ASSIGN(OneClickSigninHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_SYNC_ONE_CLICK_SIGNIN_HELPER_H_