--- a/browser/components/safebrowsing/content/sb-loader.js
+++ b/browser/components/safebrowsing/content/sb-loader.js
@@ -30,18 +30,16 @@
 # decision by deleting the provisions above and replace them with the notice
 # and other provisions required by the GPL or the LGPL. If you do not delete
 # the provisions above, a recipient may use your version of this file under
 # the terms of any one of the MPL, the GPL or the LGPL.
 #
 # ***** END LICENSE BLOCK *****
 
 var safebrowsing = {
-  appContext: null,
-
   startup: function() {
     setTimeout(function() {
       safebrowsing.deferredStartup();
     }, 2000);
     window.removeEventListener("load", safebrowsing.startup, false);
   },
 
   deferredStartup: function() {