--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1670,25 +1670,16 @@ var gBrowserInit = {
     });
 
     window.addEventListener("mousemove", MousePosTracker);
     window.addEventListener("dragover", MousePosTracker);
 
     gNavToolbox.addEventListener("customizationstarting", CustomizationHandler);
     gNavToolbox.addEventListener("customizationending", CustomizationHandler);
 
-    // End startup crash tracking after a delay to catch crashes while restoring
-    // tabs and to postpone saving the pref to disk.
-    try {
-      const startupCrashEndDelay = 30 * 1000;
-      setTimeout(Services.startup.trackStartupCrashEnd, startupCrashEndDelay);
-    } catch (ex) {
-      Cu.reportError("Could not end startup crash tracking: " + ex);
-    }
-
     SessionStore.promiseInitialized.then(() => {
       // Bail out if the window has been closed in the meantime.
       if (window.closed) {
         return;
       }
 
       // Enable the Restore Last Session command if needed
       RestoreLastSessionObserver.init();

--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -231,16 +231,18 @@ const BOOKMARKS_BACKUP_IDLE_TIME_SEC = 8
 // Minimum interval between backups.  We try to not create more than one backup
 // per interval.
 const BOOKMARKS_BACKUP_MIN_INTERVAL_DAYS = 1;
 // Maximum interval between backups.  If the last backup is older than these
 // days we will try to create a new one more aggressively.
 const BOOKMARKS_BACKUP_MAX_INTERVAL_DAYS = 3;
 // Seconds of idle time before the late idle tasks will be scheduled.
 const LATE_TASKS_IDLE_TIME_SEC = 20;
+// Time after we stop tracking startup crashes.
+const STARTUP_CRASHES_END_DELAY_MS = 30 * 1000;
 
 // Factory object
 const BrowserGlueServiceFactory = {
   _instance: null,
   createInstance: function BGSF_createInstance(outer, iid) {
     if (outer != null)
       throw Components.results.NS_ERROR_NO_AGGREGATION;
     return this._instance == null ?
@@ -1159,16 +1161,23 @@ BrowserGlue.prototype = {
       Services.tm.idleDispatchToMainThread(() => {
         this._createExtraDefaultProfile();
       });
     }
 
     Services.tm.idleDispatchToMainThread(() => {
       this._checkForDefaultBrowser();
     });
+
+    Services.tm.idleDispatchToMainThread(() => {
+      let {setTimeout} = Cu.import("resource://gre/modules/Timer.jsm", {});
+      setTimeout(function() {
+        Services.tm.idleDispatchToMainThread(Services.startup.trackStartupCrashEnd);
+      }, STARTUP_CRASHES_END_DELAY_MS);
+    });
   },
 
   /**
    * Use this function as an entry point to schedule tasks that need
    * to run once per session, at any arbitrary point in time.
    * This function will be called from an idle observer. Check the value of
    * LATE_TASKS_IDLE_TIME_SEC to see the current value for this idle
    * observer.