Returned MediaQuerySet should be const.

third_party/WebKit/Source/core/css/CSSStyleSheet.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights
  * reserved.
  *
  * 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 82 matching lines @@
   CSSRule* item(unsigned index);
 
   void clearOwnerNode() override;
 
   CSSRule* ownerRule() const override { return m_ownerRule; }
   KURL baseURL() const override;
   bool isLoading() const override;
 
   void clearOwnerRule() { m_ownerRule = nullptr; }
   Document* ownerDocument() const;
-  MediaQuerySet* mediaQueries() const { return m_mediaQueries.get(); }
+  const MediaQuerySet* mediaQueries() const { return m_mediaQueries; }
   void setMediaQueries(MediaQuerySet*);
   bool matchesMediaQueries(const MediaQueryEvaluator&);
   const MediaQueryResultList& viewportDependentMediaQueryResults() const {
     return m_viewportDependentMediaQueryResults;
   }
   const MediaQueryResultList& deviceDependentMediaQueryResults() const {
     return m_deviceDependentMediaQueryResults;
   }
   void setTitle(const String& title) { m_title = title; }
   // Set by LinkStyle iff CORS-enabled fetch of stylesheet succeeded from this
@@ skipping 84 matching lines @@
 
 DEFINE_TYPE_CASTS(CSSStyleSheet,
                   StyleSheet,
                   sheet,
                   sheet->isCSSStyleSheet(),
                   sheet.isCSSStyleSheet());
 
 }  // namespace blink
 
 #endif