Reduce risk of MediaQueryEvaluator-induced leaks.

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

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  *  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.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 35 matching lines @@
 MediaQueryMatcher::~MediaQueryMatcher()
 {
 }
 
 void MediaQueryMatcher::documentDetached()
 {
     m_document = nullptr;
     m_evaluator = nullptr;
 }
 
-PassOwnPtr<MediaQueryEvaluator> MediaQueryMatcher::createEvaluator() const
+PassOwnPtrWillBeRawPtr<MediaQueryEvaluator> MediaQueryMatcher::createEvaluator() const
 {
     if (!m_document || !m_document->frame())
         return nullptr;
 
-    return adoptPtr(new MediaQueryEvaluator(m_document->frame()));
+    return adoptPtrWillBeNoop(new MediaQueryEvaluator(m_document->frame()));
 }
 
 bool MediaQueryMatcher::evaluate(const MediaQuerySet* media)
 {
     ASSERT(!m_document || m_document->frame() || !m_evaluator);
 
     if (!media)
         return false;
 
     // Cache the evaluator to avoid allocating one per evaluation.
@@ skipping 68 matching lines @@
     for (const auto& listener : m_viewportListeners)
         listenersToNotify.append(listener);
 
     m_document->enqueueMediaQueryChangeListeners(listenersToNotify);
 }
 
 DEFINE_TRACE(MediaQueryMatcher)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_document);
+    visitor->trace(m_evaluator);
     visitor->trace(m_mediaLists);
     visitor->trace(m_viewportListeners);
 #endif
 }
 
 }