From 37c22443fb0bd9c32f01f9063cfbb597eefba1e3 Mon Sep 17 00:00:00 2001
From: Trevor Saunders <tbsaunde@tbsaunde.org>
Date: Wed, 6 Jan 2016 15:08:39 -0500
Subject: [PATCH] bug 1235965 - null check mDoc in AccessibleWrap::Shutdown()
 r=davidb

---
 accessible/windows/msaa/AccessibleWrap.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/accessible/windows/msaa/AccessibleWrap.cpp b/accessible/windows/msaa/AccessibleWrap.cpp
index 6ac115167b0d..4032f1b16fc2 100644
--- a/accessible/windows/msaa/AccessibleWrap.cpp
+++ b/accessible/windows/msaa/AccessibleWrap.cpp
@@ -91,8 +91,13 @@ void
 AccessibleWrap::Shutdown()
 {
 #ifdef _WIN64
-  if (mID != kNoID)
-    static_cast<DocAccessibleWrap*>(mDoc)->RemoveID(mID);
+  if (mID != kNoID) {
+    auto doc = static_cast<DocAccessibleWrap*>(mDoc);
+    MOZ_ASSERT(doc);
+    if (doc) {
+      doc->RemoveID(mID);
+    }
+  }
 #endif
 
   Accessible::Shutdown();