--- a/browser/base/content/test/general/browser_bug592338.js
+++ b/browser/base/content/test/general/browser_bug592338.js
@@ -1,24 +1,43 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
 const TESTROOT = "http://example.com/browser/toolkit/mozapps/extensions/test/xpinstall/";
 
-var tempScope = {};
-Components.utils.import("resource://gre/modules/LightweightThemeManager.jsm", tempScope);
-var LightweightThemeManager = tempScope.LightweightThemeManager;
+const {LightweightThemeManager} = Cu.import("resource://gre/modules/LightweightThemeManager.jsm", {});
 
-function wait_for_notification(aCallback) {
-  PopupNotifications.panel.addEventListener("popupshown", function() {
-    aCallback(PopupNotifications.panel);
-  }, {once: true});
+/**
+ * Wait for the given PopupNotification to display
+ *
+ * @param {string} name
+ *        The name of the notification to wait for.
+ *
+ * @returns {Promise}
+ *          Resolves with the notification window.
+ */
+function promisePopupNotificationShown(name) {
+  return new Promise(resolve => {
+    function popupshown() {
+      let notification = PopupNotifications.getNotification(name);
+      if (!notification) { return; }
+
+      ok(notification, `${name} notification shown`);
+      ok(PopupNotifications.isPanelOpen, "notification panel open");
+
+      PopupNotifications.panel.removeEventListener("popupshown", popupshown);
+      resolve(PopupNotifications.panel.firstChild);
+    }
+
+    PopupNotifications.panel.addEventListener("popupshown", popupshown);
+  });
 }
 
+
 var TESTS = [
 function test_install_http() {
   is(LightweightThemeManager.currentTheme, null, "Should be no lightweight theme selected");
 
   var pm = Services.perms;
   pm.add(makeURI("http://example.org/"), "install", pm.ALLOW_ACTION);
 
   gBrowser.selectedTab = gBrowser.addTab("http://example.org/browser/browser/base/content/test/general/bug592338.html");
@@ -50,30 +69,27 @@ function test_install_lwtheme() {
 
   gBrowser.selectedTab = gBrowser.addTab("https://example.com/browser/browser/base/content/test/general/bug592338.html");
   gBrowser.selectedBrowser.addEventListener("pageshow", function() {
     if (gBrowser.contentDocument.location.href == "about:blank")
       return;
 
     gBrowser.selectedBrowser.removeEventListener("pageshow", arguments.callee);
 
+    let promise = promisePopupNotificationShown("addon-installed");
     BrowserTestUtils.synthesizeMouse("#theme-install", 2, 2, {}, gBrowser.selectedBrowser);
-    let notificationBox = gBrowser.getNotificationBox(gBrowser.selectedBrowser);
-    waitForCondition(
-      () => notificationBox.getNotificationWithValue("lwtheme-install-notification"),
-      () => {
-        is(LightweightThemeManager.currentTheme.id, "test", "Should have installed the test theme");
+    promise.then(() => {
+      is(LightweightThemeManager.currentTheme.id, "test", "Should have installed the test theme");
 
-        LightweightThemeManager.currentTheme = null;
-        gBrowser.removeTab(gBrowser.selectedTab);
-        Services.perms.remove(makeURI("http://example.com/"), "install");
+      LightweightThemeManager.currentTheme = null;
+      gBrowser.removeTab(gBrowser.selectedTab);
+      Services.perms.remove(makeURI("http://example.com/"), "install");
 
-        runNextTest();
-      }
-    );
+      runNextTest();
+    });
   });
 }
 ];
 
 function runNextTest() {
   AddonManager.getAllInstalls(function(aInstalls) {
     is(aInstalls.length, 0, "Should be no active installs");