Make using WebContentsUserData simpler.

chrome/browser/ui/bookmarks/bookmark_tab_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_BOOKMARKS_BOOKMARK_TAB_HELPER_H_
 #define CHROME_BROWSER_UI_BOOKMARKS_BOOKMARK_TAB_HELPER_H_
 
 #include "chrome/browser/common/web_contents_user_data.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ skipping 48 matching lines @@
   // |bookmark_drag| is deleted since this class does not take ownership of
   // |bookmark_drag|.
   void SetBookmarkDragDelegate(
       BookmarkTabHelper::BookmarkDrag* bookmark_drag);
   // The BookmarkDragDelegate is used to forward bookmark drag and drop events
   // to extensions.
   BookmarkTabHelper::BookmarkDrag* GetBookmarkDragDelegate();
 
  private:
   explicit BookmarkTabHelper(content::WebContents* web_contents);
-  static int kUserDataKey;
   friend class WebContentsUserData<BookmarkTabHelper>;
 
   // Updates the starred state from the bookmark bar model. If the state has
   // changed, the delegate is notified.
   void UpdateStarredStateForCurrentURL();
 
   // Whether the current URL is starred.
   bool is_starred_;
 
   // Registers and unregisters us for notifications.
   content::NotificationRegistrar registrar_;
 
   // Delegate for notifying our owner (usually Browser) about stuff. Not owned
   // by us.
   BookmarkTabHelperDelegate* delegate_;
 
   // Handles drag and drop event forwarding to extensions.
   BookmarkDrag* bookmark_drag_;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkTabHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_BOOKMARKS_BOOKMARK_TAB_HELPER_H_