Make using WebContentsUserData simpler.

chrome/browser/ui/hung_plugin_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_HUNG_PLUGIN_TAB_HELPER_H_
 #define CHROME_BROWSER_UI_HUNG_PLUGIN_TAB_HELPER_H_
 
 #include <map>
 
 #include "base/file_path.h"
@@ skipping 33 matching lines @@
                                        const FilePath& plugin_path,
                                        bool is_hung) OVERRIDE;
 
   // NotificationObserver overrides.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
  private:
   explicit HungPluginTabHelper(content::WebContents* contents);
-  static int kUserDataKey;
   friend class WebContentsUserData<HungPluginTabHelper>;
 
   class InfoBarDelegate;
   friend class InfoBarDelegate;
 
   // Per-plugin state (since there could be more than one plugin hung). The
   // integer key is the child process ID of the plugin process. This maintains
   // the state for all plugins on this page that are currently hung, whether or
   // not we're currently showing the infobar.
   struct PluginState {
@@ skipping 40 matching lines @@
 
   content::NotificationRegistrar registrar_;
 
   // All currently hung plugins.
   PluginStateMap hung_plugins_;
 
   DISALLOW_COPY_AND_ASSIGN(HungPluginTabHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_HUNG_PLUGIN_TAB_HELPER_H_