BackgroundImage incorrectly returns empty url() when created on-the-fly

Source/core/css/CSSImageValue.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 48 matching lines @@
     void reResolveURL(const Document&);
 
     String customCSSText() const;
 
     bool hasFailedOrCanceledSubresources() const;
 
     bool equals(const CSSImageValue&) const;
 
     bool knownToBeOpaque(const LayoutObject*) const;
 
+    PassRefPtrWillBeRawPtr<CSSImageValue> valueWithURLMadeAbsolute()
+    {
+        return create(KURL(ParsedURLString, m_absoluteURL), m_image.get());
+    }
+
     void setInitiator(const AtomicString& name) { m_initiatorName = name; }
 
     DECLARE_TRACE_AFTER_DISPATCH();
     void restoreCachedResourceIfNeeded(Document&);
 
 private:
     CSSImageValue(const String& rawValue, const KURL&, StyleImage*);
 
     String m_relativeURL;
     String m_absoluteURL;
     Referrer m_referrer;
     RefPtrWillBeMember<StyleImage> m_image;
     bool m_accessedImage;
     AtomicString m_initiatorName;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSImageValue, isImageValue());
 
 } // namespace blink
 
 #endif // CSSImageValue_h