Move create() methods from StylePropertySet to MutableStylePropertySet.

Source/core/css/CSSParser.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 1130 matching lines @@
     RefPtr<CSSValueList> result = CSSValueList::createSpaceSeparated();
     result->append(transformValue.release());
     properties->addParsedProperty(CSSProperty(CSSPropertyWebkitTransform, result.release(), important));
     return true;
 }
 
 PassRefPtr<CSSValueList> CSSParser::parseFontFaceValue(const AtomicString& string)
 {
     if (string.isEmpty())
         return 0;
-    RefPtr<StylePropertySet> dummyStyle = StylePropertySet::create();
+    RefPtr<MutableStylePropertySet> dummyStyle = MutableStylePropertySet::create();
     if (!parseValue(dummyStyle.get(), CSSPropertyFontFamily, string, false, CSSQuirksMode, 0))
         return 0;
     return static_pointer_cast<CSSValueList>(dummyStyle->getPropertyCSSValue(CSSPropertyFontFamily));
 }
 
 bool CSSParser::parseValue(StylePropertySet* declaration, CSSPropertyID propertyID, const String& string, bool important, Document* document)
 {
     ASSERT(!string.isEmpty());
 
     CSSParserContext context(document);
@@ skipping 10549 matching lines @@
     result.lineNumber = lineNumber;
     result.content = content;
     size_t newLength = content.length();
     while (newLength > 0 && isHTMLSpace(result.content[newLength - 1]))
         --newLength;
     result.content.setLength(newLength);
     return result;
 }
 
 }