Filter out data urls in the preload scanner

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

 /*
  * 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:
  * 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 59 matching lines @@
     std::unique_ptr<PreloadRequest> preload,
     const NetworkHintsInterface& networkHintsInterface) {
   if (preload->isPreconnect()) {
     preconnectHost(preload.get(), networkHintsInterface);
     return;
   }
   // TODO(yoichio): Should preload if document is imported.
   if (!m_document->loader())
     return;
   FetchRequest request = preload->resourceRequest(m_document);
-  // TODO(dgozman): This check should go to HTMLPreloadScanner, but this
-  // requires making Document::completeURLWithOverride logic to be statically
-  // accessible.
-  if (request.url().protocolIsData())
-    return;
+
+  // Data URLs are filtered out in the preload scanner.
+  DCHECK(!request.url().protocolIsData());
+
   if (preload->resourceType() == Resource::Script ||
       preload->resourceType() == Resource::CSSStyleSheet ||
       preload->resourceType() == Resource::ImportResource)
     request.setCharset(preload->charset().isEmpty()
                            ? m_document->characterSet().getString()
                            : preload->charset());
   request.setForPreload(true, preload->discoveryTime());
   int duration = static_cast<int>(
       1000 * (monotonicallyIncreasingTime() - preload->discoveryTime()));
   DEFINE_STATIC_LOCAL(CustomCountHistogram, preloadDelayHistogram,
                       ("WebCore.PreloadDelayMs", 0, 2000, 20));
   preloadDelayHistogram.count(duration);
 
   if (preload->scriptHasInvalidTypeOrLanguage()) {
     Deprecation::countDeprecation(m_document,
                                   UseCounter::ScriptInvalidTypeOrLanguage);
   }
 
   Resource* resource =
       m_document->loader()->startPreload(preload->resourceType(), request);
   if (resource && preload->resourceType() == Resource::CSSStyleSheet) {
     Settings* settings = m_document->settings();
     if (settings && (settings->cssExternalScannerNoPreload() ||
                      settings->cssExternalScannerPreload()))
       m_cssPreloaders.add(new CSSPreloaderResourceClient(resource, this));
   }
 }
 
 }  // namespace blink