Make media query feature values more strict

Source/core/css/parser/MediaQueryParser.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MediaQueryParser_h
 #define MediaQueryParser_h
 
 #include "core/css/MediaList.h"
 #include "core/css/MediaQuery.h"
 #include "core/css/MediaQueryExp.h"
@@ skipping 14 matching lines @@
     String m_mediaType;
     OwnPtrWillBeMember<ExpressionHeapVector> m_expressions;
     String m_mediaFeature;
     CSSParserValueList m_valueList;
     bool m_mediaTypeSet;
 
 public:
     MediaQueryData();
     void clear();
     bool addExpression();
-    void addParserValue(CSSParserTokenType, const CSSParserToken&);
+    bool tryAddParserValue(CSSParserTokenType, const CSSParserToken&);
     void setMediaType(const String&);
     PassOwnPtrWillBeRawPtr<MediaQuery> takeMediaQuery();
 
     inline bool currentMediaQueryChanged() const
     {
         return (m_restrictor != MediaQuery::None || m_mediaTypeSet || m_expressions->size() > 0);
     }
 
     inline void setRestrictor(MediaQuery::Restrictor restrictor) { m_restrictor = restrictor; }
 
@@ skipping 54 matching lines @@
     const static State ReadFeatureEnd;
     const static State SkipUntilComma;
     const static State SkipUntilBlockEnd;
     const static State Done;
 
 };
 
 } // namespace blink
 
 #endif // MediaQueryParser_h