Issue 4133 - Switch to new FilterNotifier API in UI module

lib/ui.js

Index: lib/ui.js
===================================================================
--- a/lib/ui.js
+++ b/lib/ui.js
@@ -393,31 +393,35 @@ let UI = exports.UI =
    * can be added to the UI.
    */
   initDone: function()
   {
     // The icon might be added already, make sure its state is correct
     this.updateState();
 
     // Listen for pref and filters changes
-    Prefs.addListener(function(name)
+    Prefs.addListener(name =>
     {
       if (name == "enabled" || name == "defaulttoolbaraction" || name == "defaultstatusbaraction")
         this.updateState();
       else if (name == "showinstatusbar")
       {
         for (let window of this.applicationWindows)
           this.updateStatusbarIcon(window);
       }
-    }.bind(this));
-    FilterNotifier.addListener(function(action)
+    });
+
+    for (let eventName of [
+      "filter.added", "filter.removed", "filter.disabled",
+      "subscription.added", "subscription.removed", "subscription.disabled",
+      "subscription.updated", "load"
+    ])
     {
-      if (/^(filter|subscription)\.(added|removed|disabled|updated)$/.test(action) || action == "load")
-        this.updateState();
-    }.bind(this));
+      FilterNotifier.on(eventName, () => this.updateState());
+    }
 
     Notification.addShowListener(notification =>
     {
       let window = this.currentWindow;
       if (!window)
         return;
 
       let button = window.document.getElementById("abp-toolbarbutton")