diff --git a/testing/talos/talos/startup_test/sessionrestore/addon/bootstrap.js b/testing/talos/talos/startup_test/sessionrestore/addon/bootstrap.js
index b6375baee63a..4319747eff04 100644
--- a/testing/talos/talos/startup_test/sessionrestore/addon/bootstrap.js
+++ b/testing/talos/talos/startup_test/sessionrestore/addon/bootstrap.js
@@ -16,7 +16,7 @@ ChromeUtils.defineModuleGetter(this, "StartupPerformance",
   "resource:///modules/sessionstore/StartupPerformance.jsm");
 
 // Observer Service topics.
-const WINDOW_READY_TOPIC = "browser-delayed-startup-finished";
+const WINDOW_READY_TOPIC = "browser-idle-startup-tasks-finished";
 
 // Process Message Manager topics.
 const MSG_REQUEST = "session-restore-test?duration";
@@ -73,7 +73,7 @@ const sessionRestoreTest = {
     // onReady might fire before the browser window has finished initializing
     // or sometimes soon after. We handle both cases here.
     let win = Services.wm.getMostRecentWindow("navigator:browser");
-    if (!win || !win.gBrowserInit || !win.gBrowserInit.delayedStartupFinished) {
+    if (!win || !win.gBrowserInit || !win.gBrowserInit.idleTasksFinished) {
       // We didn't have a window around yet, so we'll wait until one becomes
       // available before opening the result tab.
       Services.obs.addObserver(this, WINDOW_READY_TOPIC);