Fix for CSS identifier related assert

Source/core/css/parser/BisonCSSParser.h

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 - 2010  Torch Mobile (Beijing) Co. Ltd. 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 200 matching lines @@
     void startProperty();
     void endProperty(bool isImportantFound, bool isPropertyParsed, CSSParserError = NoCSSError);
     void startEndUnknownRule();
 
     void endInvalidRuleHeader();
     void reportError(const CSSParserLocation&, CSSParserError = GeneralCSSError);
     void resumeErrorLogging() { m_ignoreErrors = false; }
     void setLocationLabel(const CSSParserLocation& location) { m_locationLabel = location; }
     const CSSParserLocation& lastLocationLabel() const { return m_locationLabel; }
 
-    void tokenToLowerCase(const CSSParserString& token);
+    void tokenToLowerCase(CSSParserString& token);
 
     void markViewportRuleBodyStart() { m_inViewport = true; }
     void markViewportRuleBodyEnd() { m_inViewport = false; }
     StyleRuleBase* createViewportRule();
 
     CSSParserLocation currentLocation() { return m_tokenizer.currentLocation(); }
 
 private:
     class StyleDeclarationScope {
         STACK_ALLOCATED();
@@ skipping 89 matching lines @@
 inline int cssyylex(void* yylval, BisonCSSParser* parser)
 {
     return parser->m_tokenizer.lex(yylval);
 }
 
 bool isValidNthToken(const CSSParserString&);
 
 } // namespace WebCore
 
 #endif // BisonCSSParser_h