Rename/tweak some StylePropertySet/CSSStyleDeclaration copying functions.

Source/core/css/StylePropertySet.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008, 2012 Apple Inc. 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 120 matching lines @@
     PassRefPtr<StylePropertySet> copyBlockProperties() const;
     void removeBlockProperties();
     bool removePropertiesInSet(const CSSPropertyID* set, unsigned length);
 
     void mergeAndOverrideOnConflict(const StylePropertySet*);
 
     CSSParserMode cssParserMode() const { return static_cast<CSSParserMode>(m_cssParserMode); }
 
     void addSubresourceStyleURLs(ListHashSet<KURL>&, StyleSheetContents* contextStyleSheet) const;
 
-    PassRefPtr<StylePropertySet> copy() const;
+    PassRefPtr<MutableStylePropertySet> mutableCopy() const;
     PassRefPtr<StylePropertySet> immutableCopyIfNeeded() const;
 
     void removeEquivalentProperties(const StylePropertySet*);
     void removeEquivalentProperties(const CSSStyleDeclaration*);
 
-    PassRefPtr<StylePropertySet> copyPropertiesInSet(const Vector<CSSPropertyID>&) const;
+    PassRefPtr<MutableStylePropertySet> copyPropertiesInSet(const Vector<CSSPropertyID>&) const;
     
     String asText() const;
 
     PropertySetCSSStyleDeclaration* cssStyleDeclaration();
     CSSStyleDeclaration* ensureCSSStyleDeclaration();
     CSSStyleDeclaration* ensureInlineCSSStyleDeclaration(const StyledElement* parentElement);
 
     bool isMutable() const { return m_isMutable; }
     bool hasCSSOMWrapper() const { return m_ownsCSSOMWrapper; }
 
@@ skipping 107 matching lines @@
 
     if (m_isMutable)
         delete static_cast<MutableStylePropertySet*>(this);
     else
         delete static_cast<ImmutableStylePropertySet*>(this);
 }
 
 } // namespace WebCore
 
 #endif // StylePropertySet_h