--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -20,16 +20,17 @@ const Ci = Components.interfaces;
 const Cc = Components.classes;
 const Cu = Components.utils;
 const Cr = Components.results;
 
 Cu.importGlobalProperties(["TextEncoder"]);
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/ExtensionContent.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "EventEmitter",
                                   "resource://devtools/shared/event-emitter.js");
 XPCOMUtils.defineLazyModuleGetter(this, "Locale",
                                   "resource://gre/modules/Locale.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Log",
                                   "resource://gre/modules/Log.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "MatchGlobs",