From 71464e7674e7733f56e77d696207be087fa548fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Wang?= <fred.wang@free.fr>
Date: Thu, 2 Jul 2015 08:50:00 -0400
Subject: [PATCH] Bug 1179483 - Fix crash in
 mozilla::a11y::HyperTextAccessible::RelationByType. r=MarcoZ

---
 accessible/generic/HyperTextAccessible.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/accessible/generic/HyperTextAccessible.cpp b/accessible/generic/HyperTextAccessible.cpp
index 04ed5656d02..71a8d58ebd0 100644
--- a/accessible/generic/HyperTextAccessible.cpp
+++ b/accessible/generic/HyperTextAccessible.cpp
@@ -1762,11 +1762,12 @@ HyperTextAccessible::RelationByType(RelationType aType)
 
   switch (aType) {
     case RelationType::NODE_CHILD_OF:
-      if (mContent->IsMathMLElement()) {
+      if (HasOwnContent() && mContent->IsMathMLElement()) {
         Accessible* parent = Parent();
         if (parent) {
           nsIContent* parentContent = parent->GetContent();
-          if (parentContent->IsMathMLElement(nsGkAtoms::mroot_)) {
+          if (parentContent &&
+              parentContent->IsMathMLElement(nsGkAtoms::mroot_)) {
             // Add a relation pointing to the parent <mroot>.
             rel.AppendTarget(parent);
           }
@@ -1774,7 +1775,7 @@ HyperTextAccessible::RelationByType(RelationType aType)
       }
       break;
     case RelationType::NODE_PARENT_OF:
-      if (mContent->IsMathMLElement(nsGkAtoms::mroot_)) {
+      if (HasOwnContent() && mContent->IsMathMLElement(nsGkAtoms::mroot_)) {
         Accessible* base = GetChildAt(0);
         Accessible* index = GetChildAt(1);
         if (base && index) {