Implement referrerpolicy attribute for img elements

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 105 matching lines @@
         , 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)
+        , m_referrerPolicy(ReferrerPolicyDefault)
     {
         ASSERT(m_mediaValues->isCached());
         if (match(m_tagImpl, imgTag)
             || match(m_tagImpl, sourceTag)) {
             m_sourceSize = SizesAttributeParser(m_mediaValues, String()).length();
             return;
         }
         if ( !match(m_tagImpl, inputTag)
             && !match(m_tagImpl, linkTag)
             && !match(m_tagImpl, scriptTag)
@@ skipping 31 matching lines @@
         if (match(m_tagImpl, sourceTag) && m_matchedMediaAttribute && pictureData.sourceURL.isEmpty()) {
             pictureData.sourceURL = m_srcsetImageCandidate.toString();
             pictureData.sourceSizeSet = m_sourceSizeSet;
             pictureData.sourceSize = m_sourceSize;
             pictureData.picked = true;
         } else if (match(m_tagImpl, imgTag) && !pictureData.sourceURL.isEmpty()) {
             setUrlToLoad(pictureData.sourceURL, AllowURLReplacement);
         }
     }
 
-    PassOwnPtr<PreloadRequest> createPreloadRequest(const KURL& predictedBaseURL, const SegmentedString& source, const ClientHintsPreferences& clientHintsPreferences, const PictureData& pictureData, const ReferrerPolicy referrerPolicy)
+    PassOwnPtr<PreloadRequest> createPreloadRequest(const KURL& predictedBaseURL, const SegmentedString& source, const ClientHintsPreferences& clientHintsPreferences, const PictureData& pictureData, const ReferrerPolicy documentReferrerPolicy)
     {
         PreloadRequest::RequestType requestType = PreloadRequest::RequestTypePreload;
         if (shouldPreconnect())
             requestType = PreloadRequest::RequestTypePreconnect;
         else if (!shouldPreload() || !m_matchedMediaAttribute)
             return nullptr;
 
         TextPosition position = TextPosition(source.currentLine(), source.currentColumn());
         FetchRequest::ResourceWidth resourceWidth;
         float sourceSize = m_sourceSize;
         bool sourceSizeSet = m_sourceSizeSet;
         if (pictureData.picked) {
             sourceSizeSet = pictureData.sourceSizeSet;
             sourceSize = pictureData.sourceSize;
         }
         if (sourceSizeSet) {
             resourceWidth.width = sourceSize;
             resourceWidth.isSet = true;
         }
 
+        // The element's 'referrerpolicy' attribute (if present) takes
+        // precedence over the document's referrer policy.
+        ReferrerPolicy referrerPolicy = m_referrerPolicy != ReferrerPolicyDefault ? m_referrerPolicy : documentReferrerPolicy;
         OwnPtr<PreloadRequest> request = PreloadRequest::create(initiatorFor(m_tagImpl), position, m_urlToLoad, predictedBaseURL, resourceType(), referrerPolicy, resourceWidth, clientHintsPreferences, requestType);
         if (isCORSEnabled())
             request->setCrossOriginEnabled(allowStoredCredentials());
         request->setCharset(charset());
         request->setDefer(m_defer);
         return request.release();
     }
 
 private:
     template<typename NameType>
@@ skipping 22 matching lines @@
             m_srcsetAttributeValue = attributeValue;
             m_srcsetImageCandidate = bestFitSourceForSrcsetAttribute(m_mediaValues->devicePixelRatio(), m_sourceSize, attributeValue);
             setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_sourceSize, m_imgSrcUrl, m_srcsetImageCandidate), AllowURLReplacement);
         } else if (match(attributeName, sizesAttr) && !m_sourceSizeSet) {
             m_sourceSize = SizesAttributeParser(m_mediaValues, attributeValue).length();
             m_sourceSizeSet = true;
             if (!m_srcsetImageCandidate.isEmpty()) {
                 m_srcsetImageCandidate = bestFitSourceForSrcsetAttribute(m_mediaValues->devicePixelRatio(), m_sourceSize, m_srcsetAttributeValue);
                 setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_sourceSize, m_imgSrcUrl, m_srcsetImageCandidate), AllowURLReplacement);
             }
+        } else if (match(attributeName, referrerpolicyAttr) && !attributeValue.isNull()) {
+            ReferrerPolicy parsedPolicy;
+            if (SecurityPolicy::referrerPolicyFromString(attributeValue, &parsedPolicy)) {
+                m_referrerPolicy = parsedPolicy;
+            } else {
+                m_referrerPolicy = ReferrerPolicyDefault;
+            }

[Yoav Weiss, 2015/08/18 21:09:21]

I believe we can replace the last 6 lines with
`SecurityPolicy::referrerPolicyFromString(attributeValue, &m_referrerPolicy)`
(since referrerPolicyFromString doesn't have any side effects on the input
referrerPolicy pointer in case it returns false)

[estark, 2015/08/19 02:53:22]

Done.

         }
     }
 
     template<typename NameType>
     void processLinkAttribute(const NameType& attributeName, const String& attributeValue)
     {
         // FIXME - Don't set rel/media/crossorigin multiple times.
         if (match(attributeName, hrefAttr)) {
             setUrlToLoad(attributeValue, DisallowURLReplacement);
         } else if (match(attributeName, relAttr)) {
@@ skipping 154 matching lines @@
     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;
     RefPtrWillBeMember<MediaValues> m_mediaValues;
+    ReferrerPolicy m_referrerPolicy;
 };
 
 TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassOwnPtr<CachedDocumentParameters> documentParameters)
     : m_documentURL(documentURL)
     , m_inStyle(false)
     , m_inPicture(false)
     , m_isAppCacheEnabled(false)
     , m_isCSPEnabled(false)
     , m_templateCount(0)
     , m_documentParameters(documentParameters)
@@ skipping 162 matching lines @@
         if (match(tagImpl, pictureTag)) {
             m_inPicture = true;
             m_pictureData = PictureData();
             return;
         }
 
         StartTagScanner scanner(tagImpl, m_documentParameters->mediaValues);
         scanner.processAttributes(token.attributes());
         if (m_inPicture)
             scanner.handlePictureSourceURL(m_pictureData);
+

[Yoav Weiss, 2015/08/18 21:09:21]

Nit: spurious new line

[estark, 2015/08/19 02:53:22]

Done.

         OwnPtr<PreloadRequest> request = scanner.createPreloadRequest(m_predictedBaseElementURL, source, m_clientHintsPreferences, m_pictureData, m_documentParameters->referrerPolicy);
         if (request)
             requests.append(request.release());
         return;
     }
     default: {
         return;
     }
     }
 }
@@ skipping 55 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;
 }
 
 }