Move most of the [Pass]RefPtr's of CSSPrimitiveValue to our transition types.

Source/core/css/CSSImageValue.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008 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 83 matching lines @@
 }
 
 String CSSImageValue::customCSSText() const
 {
     return "url(" + quoteCSSURLIfNeeded(m_url) + ")";
 }
 
 PassRefPtr<CSSValue> CSSImageValue::cloneForCSSOM() const
 {
     // NOTE: We expose CSSImageValues as URI primitive values in CSSOM to maintain old behavior.
-    RefPtr<CSSPrimitiveValue> uriValue = CSSPrimitiveValue::create(m_url, CSSPrimitiveValue::CSS_URI);
+    RefPtrWillBeRawPtr<CSSPrimitiveValue> uriValue = CSSPrimitiveValue::create(m_url, CSSPrimitiveValue::CSS_URI);
     uriValue->setCSSOMSafe();
     return uriValue.release();
 }
 
 bool CSSImageValue::knownToBeOpaque(const RenderObject* renderer) const
 {
     return m_image ? m_image->knownToBeOpaque(renderer) : false;
 }
 
 void CSSImageValue::traceAfterDispatch(Visitor* visitor)
 {
     CSSValue::traceAfterDispatch(visitor);
 }
 
 } // namespace WebCore