HTML Imports: Teach preloader about HTML Imports.

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 94 matching lines @@
     MediaQueryEvaluator mediaQueryEvaluator(mediaValues);
     return mediaQueryEvaluator.eval(mediaQueries.get());
 }
 
 class TokenPreloadScanner::StartTagScanner {
 public:
     StartTagScanner(const StringImpl* tagImpl, PassRefPtr<MediaValues> mediaValues)
         : m_tagImpl(tagImpl)
         , m_linkIsStyleSheet(false)
         , m_linkIsPreconnect(false)
+        , m_linkIsImport(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)
     {
         ASSERT(m_mediaValues->isCached());
@@ skipping 98 matching lines @@
                 m_srcsetImageCandidate = bestFitSourceForSrcsetAttribute(m_mediaValues->devicePixelRatio(), m_sourceSize, m_srcsetAttributeValue);
                 setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_sourceSize, m_imgSrcUrl, m_srcsetImageCandidate), AllowURLReplacement);
             }
         }
     }
 
     template<typename NameType>
     void processLinkAttribute(const NameType& attributeName, const String& attributeValue)
     {
         // FIXME - Don't set rel/media/crossorigin multiple times.
         if (match(attributeName, hrefAttr)) {

[Yoav Weiss, 2015/06/09 07:53:40]

Should we look into the async attribute here as well? Should loading be somewhat
different for async imports vs. blocking ones?

[yoichio, 2015/06/11 04:27:44]

The async attribute for import means that we execute later script not waiting
loading completion
 in contradiction to preloading in import means that we start loading import not
waiting former script.

             setUrlToLoad(attributeValue, DisallowURLReplacement);
         } else if (match(attributeName, relAttr)) {
             LinkRelAttribute rel(attributeValue);
             m_linkIsStyleSheet = rel.isStyleSheet() && !rel.isAlternate() && rel.iconType() == InvalidIcon && !rel.isDNSPrefetch();
             m_linkIsPreconnect = rel.isPreconnect();
+            m_linkIsImport = rel.isImport();
         } else if (match(attributeName, mediaAttr)) {
             m_matchedMediaAttribute = mediaAttributeMatches(*m_mediaValues, attributeValue);
         } else if (match(attributeName, crossoriginAttr)) {
             setCrossOriginAllowed(attributeValue);
         }
     }
 
     template<typename NameType>
     void processInputAttribute(const NameType& attributeName, const String& attributeValue)
     {
@@ skipping 72 matching lines @@
     Resource::Type resourceType() const
     {
         if (match(m_tagImpl, scriptTag))
             return Resource::Script;
         if (match(m_tagImpl, imgTag) || match(m_tagImpl, videoTag) || (match(m_tagImpl, inputTag) && m_inputIsImage))
             return Resource::Image;
         if (match(m_tagImpl, linkTag) && m_linkIsStyleSheet)
             return Resource::CSSStyleSheet;
         if (m_linkIsPreconnect)
             return Resource::Raw;
+        if (match(m_tagImpl, linkTag) && m_linkIsImport)
+            return Resource::ImportResource;
         ASSERT_NOT_REACHED();
         return Resource::Raw;
     }
 
     bool shouldPreconnect() const
     {
         return match(m_tagImpl, linkTag) && m_linkIsPreconnect && !m_urlToLoad.isEmpty();
     }
 
     bool shouldPreload() const
     {
         if (m_urlToLoad.isEmpty())
             return false;
-        if (match(m_tagImpl, linkTag) && !m_linkIsStyleSheet)
+        if (match(m_tagImpl, linkTag) && !m_linkIsStyleSheet && !m_linkIsImport)
             return false;
         if (match(m_tagImpl, inputTag) && !m_inputIsImage)
             return false;
         return true;
     }
 
     bool isCORSEnabled() const
     {
         return m_isCORSEnabled;
     }
@@ skipping 21 matching lines @@
     {
         return m_defer;
     }
 
     const StringImpl* m_tagImpl;
     String m_urlToLoad;
     ImageCandidate m_srcsetImageCandidate;
     String m_charset;
     bool m_linkIsStyleSheet;
     bool m_linkIsPreconnect;
+    bool m_linkIsImport;
     bool m_matchedMediaAttribute;
     bool m_inputIsImage;
     String m_imgSrcUrl;
     String m_srcsetAttributeValue;
     float m_sourceSize;
     bool m_sourceSizeSet;
     bool m_isCORSEnabled;
     FetchRequest::DeferOption m_defer;
     StoredCredentials m_allowCredentials;
     RefPtr<MediaValues> m_mediaValues;
@@ skipping 213 matching lines @@
         mediaValues = givenMediaValues;
     else
         mediaValues = MediaValuesCached::create(*document);
     ASSERT(mediaValues->isSafeToSendToAnotherThread());
     defaultViewportMinWidth = document->viewportDefaultMinWidth();
     viewportMetaZeroValuesQuirk = document->settings() && document->settings()->viewportMetaZeroValuesQuirk();
     viewportMetaEnabled = document->settings() && document->settings()->viewportMetaEnabled();
 }
 
 }