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 "wtf/text/StringBuilder.h"
 
 namespace blink {
 
 CSSMediaRule::CSSMediaRule(StyleRuleMedia* mediaRule, CSSStyleSheet* parent)
     : CSSConditionRule(mediaRule, parent) {}
 
 CSSMediaRule::~CSSMediaRule() {}
 
-MediaQuerySet* CSSMediaRule::mediaQueries() const {
+RefPtr<MediaQuerySet> CSSMediaRule::mediaQueries() const {
   return toStyleRuleMedia(m_groupRule.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 (m_mediaCSSOMWrapper && mediaQueries())
     m_mediaCSSOMWrapper->reattach(mediaQueries());
 }
 
 DEFINE_TRACE(CSSMediaRule) {
   visitor->trace(m_mediaCSSOMWrapper);
   CSSConditionRule::trace(visitor);
 }
 }  // namespace blink