From 5724b43f60e47a3f6dd1f235fbfc7060abfd85e0 Mon Sep 17 00:00:00 2001
From: "dbaron%dbaron.org" <dbaron%dbaron.org>
Date: Fri, 23 Dec 2005 18:54:26 +0000
Subject: [PATCH] Do not call PreserveWrapper with a null pointer.  b=319642 
 r+sr=bzbarsky

---
 dom/src/base/nsDOMClassInfo.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dom/src/base/nsDOMClassInfo.cpp b/dom/src/base/nsDOMClassInfo.cpp
index 4b3548f3e878..8d22d6267be4 100644
--- a/dom/src/base/nsDOMClassInfo.cpp
+++ b/dom/src/base/nsDOMClassInfo.cpp
@@ -4969,6 +4969,9 @@ nsDOMClassInfo::PreserveNodeWrapper(nsIXPConnectWrappedNative *aWrapper)
 {
   nsCOMPtr<nsIDOMGCParticipant> participant =
     do_QueryInterface(aWrapper->Native());
+  if (!participant)
+    // nsJSContext::PreserveWrapper needs us to null-check
+    return NS_OK;
 
   return nsDOMClassInfo::PreserveWrapper(aWrapper, IdentityKeyToWrapperFunc,
                                          participant);