From 91eb787157358336c3414b35396163e84a36492d Mon Sep 17 00:00:00 2001
From: Tim Taubert <ttaubert@mozilla.com>
Date: Fri, 1 Feb 2013 14:31:32 -0500
Subject: [PATCH] Bug 837208 - Closing a private browsing window yields
 NS_ERROR_FAILURE in removeObserver() at LightweightThemeConsumer.jsm:64;
 r=ehsan

---
 toolkit/content/LightweightThemeConsumer.jsm | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/toolkit/content/LightweightThemeConsumer.jsm b/toolkit/content/LightweightThemeConsumer.jsm
index 4f22f9a89174..3271f6ff1e4b 100644
--- a/toolkit/content/LightweightThemeConsumer.jsm
+++ b/toolkit/content/LightweightThemeConsumer.jsm
@@ -59,11 +59,14 @@ LightweightThemeConsumer.prototype = {
   },
 
   destroy: function () {
-    Components.classes["@mozilla.org/observer-service;1"]
-              .getService(Components.interfaces.nsIObserverService)
-              .removeObserver(this, "lightweight-theme-styling-update");
+    if (!PrivateBrowsingUtils.isWindowPrivate(this._win)) {
+      Components.classes["@mozilla.org/observer-service;1"]
+                .getService(Components.interfaces.nsIObserverService)
+                .removeObserver(this, "lightweight-theme-styling-update");
+
+      this._win.removeEventListener("resize", this);
+    }
 
-    this._win.removeEventListener("resize", this);
     this._win = this._doc = null;
   },