Load data URI images in an async way according to spec (take 3)

third_party/WebKit/Source/core/html/parser/HTMLSrcsetParser.cpp

 /*
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 377 matching lines @@
 static unsigned avoidDownloadIfHigherDensityResourceIsInCache(
     Vector<ImageCandidate*>& imageCandidates,
     unsigned winner,
     Document* document) {
   if (!document)
     return winner;
   for (unsigned i = imageCandidates.size() - 1; i > winner; --i) {
     KURL url = document->completeURL(
         stripLeadingAndTrailingHTMLSpaces(imageCandidates[i]->url()));
     if (memoryCache()->resourceForURL(
-            url, document->fetcher()->getCacheIdentifier()))
+            url, document->fetcher()->getCacheIdentifier()) ||
+        url.protocolIsData())
       return i;
   }
   return winner;
 }
 
 static ImageCandidate pickBestImageCandidate(
     float deviceScaleFactor,
     float sourceSize,
     Vector<ImageCandidate>& imageCandidates,
     Document* document = nullptr) {
@@ skipping 90 matching lines @@
   if (!srcAttribute.isEmpty())
     imageCandidates.append(
         ImageCandidate(srcAttribute, 0, srcAttribute.length(),
                        DescriptorParsingResult(), ImageCandidate::SrcOrigin));
 
   return pickBestImageCandidate(deviceScaleFactor, sourceSize, imageCandidates)
       .toString();
 }
 
 }  // namespace blink