From 1f1aeedae0c507ef26049113c6e49d27b56ae2c9 Mon Sep 17 00:00:00 2001
From: Kartikaya Gupta <kgupta@mozilla.com>
Date: Wed, 20 Nov 2013 12:18:09 -0500
Subject: [PATCH] Bug 940751 - Guard against potentially dereferencing a null
 pointer. r=botond

---
 widget/xpwidgets/APZCCallbackHelper.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/widget/xpwidgets/APZCCallbackHelper.cpp b/widget/xpwidgets/APZCCallbackHelper.cpp
index a5a592f640c..3e8490783fc 100644
--- a/widget/xpwidgets/APZCCallbackHelper.cpp
+++ b/widget/xpwidgets/APZCCallbackHelper.cpp
@@ -138,7 +138,7 @@ APZCCallbackHelper::GetScrollIdentifiers(const nsIContent* aContent,
                                          uint32_t* aPresShellIdOut,
                                          FrameMetrics::ViewID* aViewIdOut)
 {
-    if (!nsLayoutUtils::FindIDFor(aContent, aViewIdOut)) {
+    if (!aContent || !nsLayoutUtils::FindIDFor(aContent, aViewIdOut)) {
         return false;
     }
     nsCOMPtr<nsIDOMWindowUtils> utils = GetDOMWindowUtils(aContent);