--- a/toolkit/components/startup/tests/browser/head.js
+++ b/toolkit/components/startup/tests/browser/head.js
@@ -1,22 +1,17 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 function whenBrowserLoaded(browser, callback) {
-  browser.addEventListener("load", function onLoad(event) {
-    if (event.target == browser.contentDocument) {
-      browser.removeEventListener("load", onLoad, true);
-      executeSoon(callback);
-    }
-  }, true);
+  return BrowserTestUtils.browserLoaded(browser).then(callback);
 }
 
 function waitForOnBeforeUnloadDialog(browser, callback) {
   browser.addEventListener("DOMWillOpenModalDialog", function onModalDialog(event) {
     if (Cu.isCrossProcessWrapper(event.target)) {
       // This event fires in both the content and chrome processes. We
       // want to ignore the one in the content process.
       return;