From 9453c52c9ac9ba64b09e39bd8b936af5b2c86b62 Mon Sep 17 00:00:00 2001
From: Cameron Kaiser <classilla@floodgap.com>
Date: Mon, 15 Jan 2018 21:02:48 -0800
Subject: [PATCH] #457: M1412145

---
 layout/style/nsCSSRules.cpp | 32 +++++++++++++++++++++++++++++---
 layout/style/nsCSSRules.h   |  1 +
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/layout/style/nsCSSRules.cpp b/layout/style/nsCSSRules.cpp
index d4bf6029e..53a0aa1fb 100644
--- a/layout/style/nsCSSRules.cpp
+++ b/layout/style/nsCSSRules.cpp
@@ -210,8 +210,6 @@ ImportRule::~ImportRule()
 NS_IMPL_CYCLE_COLLECTING_ADDREF(ImportRule)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(ImportRule)
 
-NS_IMPL_CYCLE_COLLECTION(ImportRule, mMedia, mChildSheet)
-
 // QueryInterface implementation for ImportRule
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ImportRule)
   NS_INTERFACE_MAP_ENTRY(nsIDOMCSSRule)
@@ -222,6 +220,21 @@ NS_INTERFACE_MAP_END
 
 IMPL_STYLE_RULE_INHERIT(ImportRule, Rule)
 
+NS_IMPL_CYCLE_COLLECTION_CLASS(ImportRule)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ImportRule)
+  if (tmp->mChildSheet) {
+    tmp->mChildSheet->SetOwnerRule(nullptr);
+    tmp->mChildSheet = nullptr;
+  }
+  tmp->mMedia = nullptr;
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(ImportRule)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMedia)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mChildSheet)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
 #ifdef DEBUG
 /* virtual */ void
 ImportRule::List(FILE* out, int32_t aIndent) const
@@ -611,7 +624,7 @@ NS_IMPL_ADDREF_INHERITED(MediaRule, GroupRule)
 NS_IMPL_RELEASE_INHERITED(MediaRule, GroupRule)
 
 // QueryInterface implementation for MediaRule
-NS_INTERFACE_MAP_BEGIN(MediaRule)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(MediaRule)
   NS_INTERFACE_MAP_ENTRY(nsIDOMCSSRule)
   NS_INTERFACE_MAP_ENTRY(nsIDOMCSSGroupingRule)
   NS_INTERFACE_MAP_ENTRY(nsIDOMCSSConditionRule)
@@ -620,6 +633,19 @@ NS_INTERFACE_MAP_BEGIN(MediaRule)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(CSSMediaRule)
 NS_INTERFACE_MAP_END_INHERITING(GroupRule)
 
+NS_IMPL_CYCLE_COLLECTION_CLASS(MediaRule)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(MediaRule, GroupRule)
+  if (tmp->mMedia) {
+    tmp->mMedia->SetStyleSheet(nullptr);
+    tmp->mMedia = nullptr;
+  }
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(MediaRule, GroupRule)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMedia)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
 /* virtual */ void
 MediaRule::SetStyleSheet(CSSStyleSheet* aSheet)
 {
diff --git a/layout/style/nsCSSRules.h b/layout/style/nsCSSRules.h
index 1c0e22894..1bc0de60b 100644
--- a/layout/style/nsCSSRules.h
+++ b/layout/style/nsCSSRules.h
@@ -53,6 +53,7 @@ private:
   ~MediaRule();
 public:
 
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(MediaRule, GroupRule)
   NS_DECL_ISUPPORTS_INHERITED
 
   // Rule methods