Move create() methods from StylePropertySet to MutableStylePropertySet.

Source/core/svg/SVGStyledElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007, 2008 Rob Buis <buis@kde.org>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 388 matching lines @@
 PassRefPtr<CSSValue> SVGStyledElement::getPresentationAttribute(const String& name)
 {
     if (!hasAttributesWithoutUpdate())
         return 0;
 
     QualifiedName attributeName(nullAtom, name, nullAtom);
     const Attribute* attr = getAttributeItem(attributeName);
     if (!attr)
         return 0;
 
-    RefPtr<StylePropertySet> style = StylePropertySet::create(SVGAttributeMode);
+    RefPtr<MutableStylePropertySet> style = MutableStylePropertySet::create(SVGAttributeMode);
     CSSPropertyID propertyID = SVGStyledElement::cssPropertyIdForSVGAttributeName(attr->name());
     style->setProperty(propertyID, attr->value());
     RefPtr<CSSValue> cssValue = style->getPropertyCSSValue(propertyID);
     return cssValue ? cssValue->cloneForCSSOM() : 0;
 }
 
 bool SVGStyledElement::instanceUpdatesBlocked() const
 {
     return hasSVGRareData() && svgRareData()->instanceUpdatesBlocked();
 }
@@ skipping 56 matching lines @@
     Element* eventTarget = const_cast<SVGStyledElement *>(this);
     return eventTarget->hasEventListeners(eventNames().focusinEvent) || eventTarget->hasEventListeners(eventNames().focusoutEvent);
 }
 
 bool SVGStyledElement::isKeyboardFocusable(KeyboardEvent*) const
 {
     return isMouseFocusable();
 }
 
 }