Remove the CSSOM.

sky/engine/core/css/CSSComputedStyleDeclaration.cpp

 /*
  * Copyright (C) 2004 Zack Rusin <zack@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2011 Sencha, Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
@@ skipping 2343 matching lines @@
     Vector<CSSProperty, 256> list;
     list.reserveInitialCapacity(properties.size());
     for (unsigned i = 0; i < properties.size(); ++i) {
         RefPtr<CSSValue> value = getPropertyCSSValue(properties[i]);
         if (value)
             list.append(CSSProperty(properties[i], value.release(), false));
     }
     return MutableStylePropertySet::create(list.data(), list.size());
 }
 
-CSSRule* CSSComputedStyleDeclaration::parentRule() const
-{
-    return 0;
-}
-
 PassRefPtr<CSSValue> CSSComputedStyleDeclaration::getPropertyCSSValue(const String& propertyName)
 {
     CSSPropertyID propertyID = cssPropertyID(propertyName);
     if (!propertyID)
         return nullptr;
     RefPtr<CSSValue> value = getPropertyCSSValue(propertyID);
     return value ? value->cloneForCSSOM() : nullptr;
 }
 
 String CSSComputedStyleDeclaration::getPropertyValue(const String& propertyName)
@@ skipping 55 matching lines @@
     static const CSSPropertyID propertiesAfterSlashSeperator[3] = { CSSPropertyBackgroundSize, CSSPropertyBackgroundOrigin,
                                                                     CSSPropertyBackgroundClip };
 
     RefPtr<CSSValueList> list = CSSValueList::createSlashSeparated();
     list->append(valuesForShorthandProperty(StylePropertyShorthand(CSSPropertyBackground, propertiesBeforeSlashSeperator, WTF_ARRAY_LENGTH(propertiesBeforeSlashSeperator))));
     list->append(valuesForShorthandProperty(StylePropertyShorthand(CSSPropertyBackground, propertiesAfterSlashSeperator, WTF_ARRAY_LENGTH(propertiesAfterSlashSeperator))));
     return list.release();
 }
 
 } // namespace blink