Make using WebContentsUserData simpler.

chrome/browser/pepper_broker_observer.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_PEPPER_BROKER_OBSERVER_H_
 #define CHROME_BROWSER_PEPPER_BROKER_OBSERVER_H_
 
 #include "chrome/browser/common/web_contents_user_data.h"
 #include "content/public/browser/web_contents_observer.h"
 
 class PepperBrokerObserver : public content::WebContentsObserver,
                              public WebContentsUserData<PepperBrokerObserver> {
  public:
   virtual ~PepperBrokerObserver();
 
  private:
   explicit PepperBrokerObserver(content::WebContents* web_contents);
-  static int kUserDataKey;
   friend class WebContentsUserData<PepperBrokerObserver>;
 
   virtual bool RequestPpapiBrokerPermission(
       content::WebContents* web_contents,
       const GURL& url,
       const FilePath& plugin_path,
       const base::Callback<void(bool)>& callback) OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(PepperBrokerObserver);
 };
 
 #endif  // CHROME_BROWSER_PEPPER_BROKER_OBSERVER_H_