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 213 matching lines @@
   while (reducedLength &&
          isHTMLSpace<UChar>(string[offset + reducedLength - 1]))
     --reducedLength;
 
   return string.substring(offset, reducedLength);
 }
 
 void CSSPreloadScanner::emitRule(const SegmentedString& source) {
   if (equalIgnoringCase(m_rule, "import")) {
     String url = parseCSSStringOrURL(m_ruleValue.toString());
-    if (!url.isEmpty()) {

[Yoav Weiss, 2016/10/24 14:43:54]

Why create a request for empty URLs?

[Charlie Harrison, 2016/10/24 14:49:31]

I moved the isEmpty check to the PreloadRequest class.

[Yoav Weiss, 2016/10/24 15:00:32]

OK, thanks!

-      TextPosition position =
-          TextPosition(source.currentLine(), source.currentColumn());
-      std::unique_ptr<PreloadRequest> request =
-          PreloadRequest::create(FetchInitiatorTypeNames::css, position, url,
-                                 *m_predictedBaseElementURL,
-                                 Resource::CSSStyleSheet, m_referrerPolicy);
+    TextPosition position =
+        TextPosition(source.currentLine(), source.currentColumn());
+    std::unique_ptr<PreloadRequest> request = PreloadRequest::create(
+        FetchInitiatorTypeNames::css, position, url, *m_predictedBaseElementURL,
+        Resource::CSSStyleSheet, m_referrerPolicy);
+    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 69 matching lines @@
                              currentPreloadCount);
   }
 }
 
 DEFINE_TRACE(CSSPreloaderResourceClient) {
   visitor->trace(m_preloader);
   ResourceOwner<CSSStyleSheetResource>::trace(visitor);
 }
 
 }  // namespace blink