Remove CSSStyleDeclaration::copyProperties()

Source/core/css/PropertySetCSSStyleDeclaration.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Research In Motion Limited. 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.
  *
@@ skipping 250 matching lines @@
     if (changed)
         mutationScope.enqueueMutationRecord();
 }
 
 StyleSheetContents* AbstractPropertySetCSSStyleDeclaration::contextStyleSheet() const
 {
     CSSStyleSheet* cssStyleSheet = parentStyleSheet();
     return cssStyleSheet ? cssStyleSheet->contents() : 0;
 }
 
-PassRefPtrWillBeRawPtr<MutableStylePropertySet> AbstractPropertySetCSSStyleDeclaration::copyProperties() const
-{
-    return propertySet().mutableCopy();
-}
-
 bool AbstractPropertySetCSSStyleDeclaration::cssPropertyMatches(CSSPropertyID propertyID, const CSSValue* propertyValue) const
 {
     return propertySet().propertyMatches(propertyID, propertyValue);
 }
 
 DEFINE_TRACE(AbstractPropertySetCSSStyleDeclaration)
 {
     CSSStyleDeclaration::trace(visitor);
 }
 
@@ skipping 101 matching lines @@
 }
 #endif
 
 DEFINE_TRACE(InlineCSSStyleDeclaration)
 {
     visitor->trace(m_parentElement);
     AbstractPropertySetCSSStyleDeclaration::trace(visitor);
 }
 
 } // namespace blink