Lower priority of async scripts

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 93 matching lines @@
 class TokenPreloadScanner::StartTagScanner {
 public:
     StartTagScanner(const StringImpl* tagImpl, PassRefPtr<MediaValues> mediaValues)
         : m_tagImpl(tagImpl)
         , m_linkIsStyleSheet(false)
         , m_matchedMediaAttribute(true)
         , m_inputIsImage(false)
         , m_sourceSize(0)
         , m_sourceSizeSet(false)
         , m_isCORSEnabled(false)
+        , m_defer(FetchRequest::NoDefer)
         , m_allowCredentials(DoNotAllowStoredCredentials)
         , m_mediaValues(mediaValues)
     {
         if (match(m_tagImpl, imgTag)
             || match(m_tagImpl, sourceTag)) {
             if (RuntimeEnabledFeatures::pictureSizesEnabled())
                 m_sourceSize = SizesAttributeParser(m_mediaValues, String()).length();
             return;
         }
         if ( !match(m_tagImpl, inputTag)
@@ skipping 39 matching lines @@
     {
         if (!shouldPreload() || !m_matchedMediaAttribute)
             return nullptr;
 
         TRACE_EVENT_INSTANT1("net", "PreloadRequest", "url", m_urlToLoad.ascii());
         TextPosition position = TextPosition(source.currentLine(), source.currentColumn());
         OwnPtr<PreloadRequest> request = PreloadRequest::create(initiatorFor(m_tagImpl), position, m_urlToLoad, predictedBaseURL, resourceType());
         if (isCORSEnabled())
             request->setCrossOriginEnabled(allowStoredCredentials());
         request->setCharset(charset());
+        request->setDefer(m_defer);
         return request.release();
     }
 
 private:
     template<typename NameType>
     void processScriptAttribute(const NameType& attributeName, const String& attributeValue)
     {
         // FIXME - Don't set crossorigin multiple times.
         if (match(attributeName, srcAttr))
             setUrlToLoad(attributeValue, DisallowURLReplacement);
         else if (match(attributeName, crossoriginAttr))
             setCrossOriginAllowed(attributeValue);
+        else if (match(attributeName, asyncAttr))
+            setDefer(FetchRequest::LazyLoad);
+        else if (match(attributeName, deferAttr))
+            setDefer(FetchRequest::LazyLoad);
     }
 
     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);
         } else if (match(attributeName, crossoriginAttr)) {
             setCrossOriginAllowed(attributeValue);
@@ skipping 135 matching lines @@
 
     void setCrossOriginAllowed(const String& corsSetting)
     {
         m_isCORSEnabled = true;
         if (!corsSetting.isNull() && equalIgnoringCase(stripLeadingAndTrailingHTMLSpaces(corsSetting), "use-credentials"))
             m_allowCredentials = AllowStoredCredentials;
         else
             m_allowCredentials = DoNotAllowStoredCredentials;
     }
 
+    void setDefer(FetchRequest::DeferOption defer)
+    {
+        m_defer = defer;
+    }
+
+    bool defer() const
+    {
+        return m_defer;
+    }
+
     const StringImpl* m_tagImpl;
     String m_urlToLoad;
     ImageCandidate m_srcsetImageCandidate;
     String m_charset;
     bool m_linkIsStyleSheet;
     bool m_matchedMediaAttribute;
     bool m_inputIsImage;
     String m_imgSrcUrl;
     String m_srcsetAttributeValue;
     unsigned m_sourceSize;
     bool m_sourceSizeSet;
     bool m_isCORSEnabled;
+    FetchRequest::DeferOption m_defer;
     StoredCredentials m_allowCredentials;
     RefPtr<MediaValues> m_mediaValues;
 };
 
 TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassRefPtr<MediaValues> mediaValues)
     : m_documentURL(documentURL)
     , m_inStyle(false)
     , m_inPicture(false)
     , m_templateCount(0)
     , m_mediaValues(mediaValues)
@@ skipping 138 matching lines @@
         if (m_token.type() == HTMLToken::StartTag)
             m_tokenizer->updateStateFor(attemptStaticStringCreation(m_token.name(), Likely8Bit));
         m_scanner.scan(m_token, m_source, requests);
         m_token.clear();
     }
 
     preloader->takeAndPreload(requests);
 }
 
 }