Move MediaQuery classes off BlinkGC heap

third_party/WebKit/Source/core/css/CSSMediaRule.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 2012 Apple Computer, Inc.
  * Copyright (C) 2006 Samuel Weinig (sam@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 14 matching lines @@
 #include "core/css/StyleRule.h"
 #include "platform/wtf/text/StringBuilder.h"
 
 namespace blink {
 
 CSSMediaRule::CSSMediaRule(StyleRuleMedia* media_rule, CSSStyleSheet* parent)
     : CSSConditionRule(media_rule, parent) {}
 
 CSSMediaRule::~CSSMediaRule() {}
 
-MediaQuerySet* CSSMediaRule::MediaQueries() const {
+RefPtr<MediaQuerySet> CSSMediaRule::MediaQueries() const {
   return ToStyleRuleMedia(group_rule_.Get())->MediaQueries();
 }
 
 String CSSMediaRule::cssText() const {
   StringBuilder result;
   result.Append("@media ");
   if (MediaQueries()) {
     result.Append(MediaQueries()->MediaText());
     result.Append(' ');
   }
@@ skipping 22 matching lines @@
   CSSConditionRule::Reattach(rule);
   if (media_cssom_wrapper_ && MediaQueries())
     media_cssom_wrapper_->Reattach(MediaQueries());
 }
 
 DEFINE_TRACE(CSSMediaRule) {
   visitor->Trace(media_cssom_wrapper_);
   CSSConditionRule::Trace(visitor);
 }
 }  // namespace blink