Issue 3379 - filterListener unit tests are broken

lib/elemHide.js

Index: lib/elemHide.js
===================================================================
--- a/lib/elemHide.js
+++ b/lib/elemHide.js
@@ -21,47 +21,47 @@
 
 Cu.import("resource://gre/modules/Services.jsm");
 
-let {Utils} = require("utils");
-let {IO} = require("io");
-let {Prefs} = require("prefs");
-let {ElemHideException} = require("filterClasses");
-let {FilterNotifier} = require("filterNotifier");
+var {Utils} = require("utils");
+var {IO} = require("io");
+var {Prefs} = require("prefs");
+var {ElemHideException} = require("filterClasses");
+var {FilterNotifier} = require("filterNotifier");
 
 /**
  * Lookup table, filters by their associated key
  * @type Object
  */
-let filterByKey = Object.create(null);
+var filterByKey = Object.create(null);
 
 /**
  * Lookup table, keys of the filters by filter text
  * @type Object
  */
-let keyByFilter = Object.create(null);
+var keyByFilter = Object.create(null);
 
 /**
  * Lookup table, keys are known element hiding exceptions
  * @type Object
  */
-let knownExceptions = Object.create(null);
+var knownExceptions = Object.create(null);
 
 /**
  * Lookup table, lists of element hiding exceptions by selector
  * @type Object
  */
-let exceptions = Object.create(null);
+var exceptions = Object.create(null);
 
 /**
  * Currently applied stylesheet URL
  * @type nsIURI
  */
-let styleURL = null;
+var styleURL = null;
 
 /**
  * Element hiding component
  * @class
  */
-let ElemHide = exports.ElemHide =
+var ElemHide = exports.ElemHide =
 {
   /**
    * Indicates whether filters have been added or removed since the last apply() call.