Issue 3868 - Use the new FilterNotifier API

lib/filterComposer.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 154 matching lines @@
 function updateContextMenu(page, filter)
 {
   page.contextMenus.remove(contextMenuItem);
 
   if (typeof filter == "undefined")
     filter = checkWhitelisted(page);
   if (!filter && Prefs.shouldShowBlockElementMenu && readyPages.has(page))
     page.contextMenus.create(contextMenuItem);
 }
 
-FilterNotifier.addListener((action, page, filter) =>
-{
-  if (action == "page.WhitelistingStateRevalidate")
-    updateContextMenu(page, filter);
-});
+FilterNotifier.on("page.WhitelistingStateRevalidate", updateContextMenu);
 
 Prefs.on("shouldShowBlockElementMenu", () =>
 {
   ext.pages.query({}, pages =>
   {
     for (let page of pages)
       updateContextMenu(page);
   });
 });
 
@@ skipping 49 matching lines @@
     baseURL: message.baseURL,
     page:    sender.page,
     frame:   sender.frame
   });
 });
 
 ext.pages.onLoading.addListener(page =>
 {
   page.sendMessage({type: "composer.content.finished"});
 });