Avoid invoking ResourceFetcher::cachedResource() with a null URL

third_party/WebKit/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 62 matching lines @@
             m_cachedImage = StyleFetchedImage::create(cachedImage, document, request.url());
         else
             m_cachedImage = StyleInvalidImage::create(url());
     }
 
     return m_cachedImage.get();
 }
 
 void CSSImageValue::restoreCachedResourceIfNeeded(Document& document) const
 {
-    if (m_isCachePending || !m_cachedImage || !document.fetcher())
+    if (m_isCachePending || !m_cachedImage || !document.fetcher() || m_absoluteURL.isNull())
         return;
     if (document.fetcher()->cachedResource(KURL(ParsedURLString, m_absoluteURL)))
         return;
 
     ImageResource* resource = m_cachedImage->cachedImage();
     if (!resource)
         return;
 
     FetchRequest request(ResourceRequest(m_absoluteURL), m_initiatorName.isEmpty() ? FetchInitiatorTypeNames::css : m_initiatorName, resource->options());
     MixedContentChecker::shouldBlockFetch(document.frame(), resource->lastResourceRequest(),
@@ skipping 36 matching lines @@
     KURL url = document.completeURL(m_relativeURL);
     AtomicString urlString(url.getString());
     if (urlString == m_absoluteURL)
         return;
     m_absoluteURL = urlString;
     m_isCachePending = true;
     m_cachedImage.clear();
 }
 
 } // namespace blink