Fix-up some code relating to SRI double-requesting scripts

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

 /*
  * Copyright (C) 2008 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 203 matching lines @@
     {
         // FIXME - Don't set crossorigin multiple times.
         if (match(attributeName, srcAttr))
             setUrlToLoad(attributeValue, DisallowURLReplacement);
         else if (match(attributeName, crossoriginAttr))
             setCrossOrigin(attributeValue);
         else if (match(attributeName, asyncAttr))
             setDefer(FetchRequest::LazyLoad);
         else if (match(attributeName, deferAttr))
             setDefer(FetchRequest::LazyLoad);
+        // Note that only scripts need to have the integrity metadata set on
+        // preloads. This is because script resources fetches, and only script
+        // resource fetches, need to re-request resources if a cached version
+        // has different metadata (including empty) from the metadata on the
+        // request. See the comment before the call to
+        // mustRefetchDueToIntegrityMismatch() in
+        // Source/core/fetch/ResourceFetcher.cpp for a more complete
+        // explanation.
         else if (match(attributeName, integrityAttr))
             SubresourceIntegrity::parseIntegrityAttribute(attributeValue, m_integrityMetadata);
     }
 
     template<typename NameType>
     void processImgAttribute(const NameType& attributeName, const String& attributeValue)
     {
         if (match(attributeName, srcAttr) && m_imgSrcUrl.isNull()) {
             m_imgSrcUrl = attributeValue;
             setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_sourceSize, attributeValue, m_srcsetImageCandidate), AllowURLReplacement);
@@ skipping 141 matching lines @@
         return true;
     }
     void setCrossOrigin(const String& corsSetting)
     {
         m_crossOrigin = crossOriginAttributeValue(corsSetting);
     }
 
     void setDefer(FetchRequest::DeferOption defer)
     {
         m_defer = defer;
-
     }
 
     bool defer() const
     {
         return m_defer;
     }
 
     const StringImpl* m_tagImpl;
     String m_urlToLoad;
     ImageCandidate m_srcsetImageCandidate;
@@ skipping 263 matching lines @@
     else
         mediaValues = MediaValuesCached::create(*document);
     ASSERT(mediaValues->isSafeToSendToAnotherThread());
     defaultViewportMinWidth = document->viewportDefaultMinWidth();
     viewportMetaZeroValuesQuirk = document->settings() && document->settings()->viewportMetaZeroValuesQuirk();
     viewportMetaEnabled = document->settings() && document->settings()->viewportMetaEnabled();
     referrerPolicy = ReferrerPolicyDefault;
 }
 
 }