Rename/tweak some StylePropertySet/CSSStyleDeclaration copying functions.

Source/core/css/CSSStyleDeclaration.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 13 matching lines @@
 #include "CSSPropertyNames.h"
 #include "bindings/v8/ScriptWrappable.h"
 #include <wtf/Forward.h>
 
 namespace WebCore {
 
 class CSSProperty;
 class CSSRule;
 class CSSStyleSheet;
 class CSSValue;
+class MutableStylePropertySet;
 class StylePropertySet;
 class StyledElement;
 
 typedef int ExceptionCode;
 
 class CSSStyleDeclaration : public ScriptWrappable {
     WTF_MAKE_NONCOPYABLE(CSSStyleDeclaration); WTF_MAKE_FAST_ALLOCATED;
 public:
     virtual ~CSSStyleDeclaration() { }
 
@@ skipping 13 matching lines @@
     virtual void setProperty(const String& propertyName, const String& value, const String& priority, ExceptionCode&) = 0;
     virtual String removeProperty(const String& propertyName, ExceptionCode&) = 0;
 
     // CSSPropertyID versions of the CSSOM functions to support bindings and editing.
     // Use the non-virtual methods in the concrete subclasses when possible.
     // The CSSValue returned by this function should not be exposed to the web as it may be used by multiple documents at the same time.
     virtual PassRefPtr<CSSValue> getPropertyCSSValueInternal(CSSPropertyID) = 0;
     virtual String getPropertyValueInternal(CSSPropertyID) = 0;
     virtual void setPropertyInternal(CSSPropertyID, const String& value, bool important, ExceptionCode&) = 0;
 
-    virtual PassRefPtr<StylePropertySet> copy() const = 0;
+    virtual PassRefPtr<MutableStylePropertySet> copyProperties() const = 0;
 
     virtual bool cssPropertyMatches(CSSPropertyID, const CSSValue*) const = 0;
     virtual CSSStyleSheet* parentStyleSheet() const { return 0; }
 
     virtual void reportMemoryUsage(MemoryObjectInfo*) const = 0;
 
 protected:
     CSSStyleDeclaration()
     {
         ScriptWrappable::init(this);
     }
 };
 
 } // namespace WebCore
 
 #endif // CSSStyleDeclaration_h