Issue 3839 - Adapt for Prefs event changes

background.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 75 matching lines @@
       },
       get appLocale()
       {
         return parent.ext.i18n.getMessage("@@ui_locale").replace(/_/g, "-");
       }
     }
   };
 
   modules.prefs = {
     Prefs: {
-      onChanged: new Notifier()
+      _listeners: Object.create(null),
+
+      on: function(preference, callback)
+      {
+        if (preference in this._listeners)
+          this._listeners[preference].push(callback);
+        else
+          this._listeners[preference] = [callback];
+      }
     }
   };
   var prefs = {
     notifications_ignoredcategories: (params.showNotificationUI) ? ["*"] : [],
     notifications_showui: params.showNotificationUI,
     safari_contentblocker: false,
     shouldShowBlockElementMenu: true,
     show_devtools_panel: true,
     subscriptions_exceptionsurl: "https://easylist-downloads.adblockplus.org/exceptionrules.txt"
   };
   Object.keys(prefs).forEach(function(key)
   {
     Object.defineProperty(modules.prefs.Prefs, key, {
       get: function()
       {
         return prefs[key];
       },
       set: function(value)
       {
         prefs[key] = value;
-        modules.prefs.Prefs.onChanged.triggerListeners(key);
-        return prefs[key];
+
+        var listeners = modules.prefs.Prefs._listeners[key];
+        if (listeners)
+          for (var i = 0; i < listeners.length; i++)
+            listeners[i]();
       }
     });
   });
 
   modules.notification = {
     Notification: {
       toggleIgnoreCategory: function(category)
       {
         var categories = prefs.notifications_ignoredcategories;
         var index = categories.indexOf(category);
@@ skipping 341 matching lines @@
 
   if (params.safariContentBlocker)
   {
     global.safari = {
       extension: {
         setContentBlocker: function() {}
       }
     };
   }
 })(this);