From 7df9e4e10a497a6811161a114de57c345d33e078 Mon Sep 17 00:00:00 2001
From: Andrew McCreight <continuation@gmail.com>
Date: Wed, 18 Jun 2014 15:33:30 -0700
Subject: [PATCH] Bug 1011391 - Clear rule cascades in nsCSSStyleSheet's
 Unlink. r=bz

---
 layout/style/nsCSSStyleSheet.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/layout/style/nsCSSStyleSheet.cpp b/layout/style/nsCSSStyleSheet.cpp
index 1d517484b9f..1d709a1b646 100644
--- a/layout/style/nsCSSStyleSheet.cpp
+++ b/layout/style/nsCSSStyleSheet.cpp
@@ -1149,6 +1149,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsCSSStyleSheet)
   tmp->DropRuleCollection();
   tmp->UnlinkInner();
   tmp->mScopeElement = nullptr;
+  tmp->ClearRuleCascades();
   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsCSSStyleSheet)