Filter out data urls in the preload scanner

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

 /*
  * Copyright (C) 2008, 2010 Apple Inc. All Rights Reserved.
  * Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
  * Copyright (C) 2010 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.
@@ skipping 220 matching lines @@
 void CSSPreloadScanner::emitRule(const SegmentedString& source) {
   if (equalIgnoringCase(m_rule, "import")) {
     String url = parseCSSStringOrURL(m_ruleValue.toString());
     if (!url.isEmpty()) {
       TextPosition position =
           TextPosition(source.currentLine(), source.currentColumn());
       std::unique_ptr<PreloadRequest> request =
           PreloadRequest::create(FetchInitiatorTypeNames::css, position, url,
                                  *m_predictedBaseElementURL,
                                  Resource::CSSStyleSheet, m_referrerPolicy);
-      // FIXME: Should this be including the charset in the preload request?
-      m_requests->append(std::move(request));
+      if (request) {
+        // FIXME: Should this be including the charset in the preload request?
+        m_requests->append(std::move(request));
+      }
     }
     m_state = Initial;
   } else if (equalIgnoringCase(m_rule, "charset"))
     m_state = Initial;
   else
     m_state = DoneParsingImportRules;
   m_rule.clear();
   m_ruleValue.clear();
 }
 
@@ skipping 67 matching lines @@
                              currentPreloadCount);
   }
 }
 
 DEFINE_TRACE(CSSPreloaderResourceClient) {
   visitor->trace(m_preloader);
   ResourceOwner<CSSStyleSheetResource>::trace(visitor);
 }
 
 }  // namespace blink