Remove CSSOM mutability in StyleRule.

sky/engine/core/css/parser/BisonCSSParser-in.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 1662 matching lines @@
             // See http://dev.w3.org/csswg/css3-fonts/#font-family-desc
             clearProperties();
             return 0;
         }
     }
     RefPtr<StyleRuleFontFace> rule = StyleRuleFontFace::create();
     rule->setProperties(createStylePropertySet());
     clearProperties();
     StyleRuleFontFace* result = rule.get();
     m_parsedRules.append(rule.release());
-    if (m_styleSheet)
-        m_styleSheet->setHasFontFaceRule(true);
     return result;
 }
 
 CSSParserSelector* BisonCSSParser::rewriteSpecifiersWithNamespaceIfNeeded(CSSParserSelector* specifiers)
 {
     if (m_defaultNamespace != starAtom)
         return rewriteSpecifiersWithElementName(nullAtom, starAtom, specifiers, /*tagIsForNamespaceRule*/true);
     return specifiers;
 }
 
@@ skipping 123 matching lines @@
         m_observer->endProperty(isImportantFound, isPropertyParsed, m_tokenizer.safeUserStringTokenOffset(), errorType);
 }
 
 void BisonCSSParser::startEndUnknownRule()
 {
     if (m_observer)
         m_observer->startEndUnknownRule();
 }
 
 }