Apply meta tag referrer policy for preloaded requests

Source/core/html/parser/HTMLPreloadScanner.cpp

Index: Source/core/html/parser/HTMLPreloadScanner.cpp
diff --git a/Source/core/html/parser/HTMLPreloadScanner.cpp b/Source/core/html/parser/HTMLPreloadScanner.cpp
index 44395718c6253b2dd08370460cb8b2d26e62e11a..34b0bdc34e1afbd13a80030ffb5efc5ccc85c79a 100644
--- a/Source/core/html/parser/HTMLPreloadScanner.cpp
+++ b/Source/core/html/parser/HTMLPreloadScanner.cpp
@@ -450,14 +450,14 @@ void TokenPreloadScanner::rewindTo(TokenPreloadScannerCheckpoint checkpointIndex
     m_checkpoints.clear();
 }
 
-void TokenPreloadScanner::scan(const HTMLToken& token, const SegmentedString& source, PreloadRequestStream& requests)
+void TokenPreloadScanner::scan(const HTMLToken& token, const SegmentedString& source, PreloadRequestStream& requests, String* preloadedReferrerPolicy)
 {
-    scanCommon(token, source, requests);
+    scanCommon(token, source, requests, preloadedReferrerPolicy);
 }
 
-void TokenPreloadScanner::scan(const CompactHTMLToken& token, const SegmentedString& source, PreloadRequestStream& requests)
+void TokenPreloadScanner::scan(const CompactHTMLToken& token, const SegmentedString& source, PreloadRequestStream& requests, String* preloadedReferrerPolicy)
 {
-    scanCommon(token, source, requests);
+    scanCommon(token, source, requests, preloadedReferrerPolicy);
 }
 
 static void handleMetaViewport(const String& attributeValue, CachedDocumentParameters* documentParameters)
@@ -473,8 +473,8 @@ static void handleMetaViewport(const String& attributeValue, CachedDocumentParam
     cachedMediaValues->setViewportWidth(constraints.layoutSize.width());
 }
 
-template<typename Token>
-void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString& source, PreloadRequestStream& requests)
+template <typename Token>
+void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString& source, PreloadRequestStream& requests, String* preloadedReferrerPolicy)
 {
     if (!m_documentParameters->doHtmlPreloadScanning)
         return;
@@ -554,6 +554,11 @@ void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString&
                     handleMetaViewport(String(contentAttribute->value), m_documentParameters.get());
                 return;
             }
+            if (nameAttribute && equalIgnoringCase(String(nameAttribute->value), "referrer")) {
+                const typename Token::Attribute* contentAttribute = token.getAttributeItem(contentAttr);
+                if (contentAttribute)
+                    *preloadedReferrerPolicy = String(contentAttribute->value).isolatedCopy();
+            }
         }
 
         if (match(tagImpl, pictureTag)) {
@@ -613,14 +618,18 @@ void HTMLPreloadScanner::scan(ResourcePreloader* preloader, const KURL& starting
         m_scanner.setPredictedBaseElementURL(startingBaseElementURL);
 
     PreloadRequestStream requests;
+    String preloadedReferrerPolicy;
 
     while (m_tokenizer->nextToken(m_source, m_token)) {
         if (m_token.type() == HTMLToken::StartTag)
             m_tokenizer->updateStateFor(attemptStaticStringCreation(m_token.name(), Likely8Bit));
-        m_scanner.scan(m_token, m_source, requests);
+        m_scanner.scan(m_token, m_source, requests, &preloadedReferrerPolicy);
         m_token.clear();
     }
 
+    if (!preloadedReferrerPolicy.isEmpty())
+        preloader->preloadReferrerPolicy(preloadedReferrerPolicy);
+
     preloader->takeAndPreload(requests);
 }