From 62d55e4df999eeec39b13b2e3898ab6ee56af907 Mon Sep 17 00:00:00 2001
From: Tim Taubert <ttaubert@mozilla.com>
Date: Wed, 19 Sep 2012 17:33:55 +0200
Subject: [PATCH] Bug 780123 - bustage fix for xpcshell test shutdown; r=me

---
 browser/modules/BrowserNewTabPreloader.jsm | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/browser/modules/BrowserNewTabPreloader.jsm b/browser/modules/BrowserNewTabPreloader.jsm
index 4faa637aae9..2c112bc2556 100644
--- a/browser/modules/BrowserNewTabPreloader.jsm
+++ b/browser/modules/BrowserNewTabPreloader.jsm
@@ -67,8 +67,10 @@ let Preferences = {
   },
 
   uninit: function Preferences_uninit() {
-    this._branch.removeObserver("", this);
-    this._branch = null;
+    if (this._branch) {
+      this._branch.removeObserver("", this);
+      this._branch = null;
+    }
   },
 
   observe: function Preferences_observe(aSubject, aTopic, aData) {