NOT FOR LANDING Experiment with allocating SVGImageForContainer on demand

Source/core/css/CSSImageSetValue.cpp

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 97 matching lines @@
         // All forms of scale should be included: Page::pageScaleFactor(), LocalFrame::pageZoomFactor(),
         // and any CSS transforms. https://bugs.webkit.org/show_bug.cgi?id=81698
         ImageWithScale image = bestImageForScaleFactor();
         FetchRequest request(ResourceRequest(document->completeURL(image.imageURL)), FetchInitiatorTypeNames::css, options);
         request.mutableResourceRequest().setHTTPReferrer(image.referrer);
 
         if (options.corsEnabled == IsCORSEnabled)
             request.setCrossOriginAccessControl(document->securityOrigin(), options.allowCredentials, options.credentialsRequested);
 
         if (ResourcePtr<ImageResource> cachedImage = ImageResource::fetch(request, document->fetcher())) {
-            m_imageSet = StyleFetchedImageSet::create(cachedImage.get(), image.scaleFactor, this);
+            m_imageSet = StyleFetchedImageSet::create(cachedImage.get(), image.scaleFactor, this, request.url());
             m_accessedBestFitImage = true;
         }
     }
 
     return (m_imageSet && m_imageSet->isImageResourceSet()) ? toStyleFetchedImageSet(m_imageSet) : nullptr;
 }
 
 StyleFetchedImageSet* CSSImageSetValue::cachedImageSet(Document* document, float deviceScaleFactor)
 {
     return cachedImageSet(document, deviceScaleFactor, ResourceFetcher::defaultResourceOptions());
@@ skipping 53 matching lines @@
     return true;
 }
 
 DEFINE_TRACE_AFTER_DISPATCH(CSSImageSetValue)
 {
     visitor->trace(m_imageSet);
     CSSValueList::traceAfterDispatch(visitor);
 }
 
 } // namespace blink