From 7786b357e982d1961015ed9d4c0b4b05c867f6ce Mon Sep 17 00:00:00 2001
From: Andrea Marchesini <amarchesini@mozilla.com>
Date: Wed, 8 Aug 2018 08:22:37 +0200
Subject: [PATCH] Bug 1480179 - Fix the traverse() of MediaQueryList in
 nsDocument, r=smaug

---
 dom/base/nsDocument.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index 24e6e818a849..56a59f63bcef 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -1959,7 +1959,8 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(nsDocument)
   // methods.
   for (MediaQueryList* mql = tmp->mDOMMediaQueryLists.getFirst(); mql;
        mql = static_cast<LinkedListElement<MediaQueryList>*>(mql)->getNext()) {
-    if (mql->HasListeners()) {
+    if (mql->HasListeners() &&
+        NS_SUCCEEDED(mql->CheckInnerWindowCorrectness())) {
       NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mDOMMediaQueryLists item");
       cb.NoteXPCOMChild(mql);
     }