Reland: Make the HTMLDocumentParser yield more aggressively

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 356 matching lines @@
     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_isAppCacheEnabled(false)
+    , m_isCSPEnabled(false)
     , m_templateCount(0)
     , m_mediaValues(mediaValues)
 {
 }
 
 TokenPreloadScanner::~TokenPreloadScanner()
 {
 }
 
 TokenPreloadScannerCheckpoint TokenPreloadScanner::createCheckpoint()
 {
     TokenPreloadScannerCheckpoint checkpoint = m_checkpoints.size();
-    m_checkpoints.append(Checkpoint(m_predictedBaseElementURL, m_inStyle, m_isAppCacheEnabled, m_templateCount));
+    m_checkpoints.append(Checkpoint(m_predictedBaseElementURL, m_inStyle, m_isAppCacheEnabled, m_isCSPEnabled, m_templateCount));
     return checkpoint;
 }
 
 void TokenPreloadScanner::rewindTo(TokenPreloadScannerCheckpoint checkpointIndex)
 {
     ASSERT(checkpointIndex < m_checkpoints.size()); // If this ASSERT fires, checkpointIndex is invalid.
     const Checkpoint& checkpoint = m_checkpoints[checkpointIndex];
     m_predictedBaseElementURL = checkpoint.predictedBaseElementURL;
     m_inStyle = checkpoint.inStyle;
     m_isAppCacheEnabled = checkpoint.isAppCacheEnabled;
+    m_isCSPEnabled = checkpoint.isCSPEnabled;
     m_templateCount = checkpoint.templateCount;
     m_cssScanner.reset();
     m_checkpoints.clear();
 }
 
 void TokenPreloadScanner::scan(const HTMLToken& token, const SegmentedString& source, PreloadRequestStream& requests)
 {
     scanCommon(token, source, requests);
 }
 
 void TokenPreloadScanner::scan(const CompactHTMLToken& token, const SegmentedString& source, PreloadRequestStream& requests)
 {
     scanCommon(token, source, requests);
 }
 
 template<typename Token>
 void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString& source, PreloadRequestStream& requests)
 {
     // Disable preload for documents with AppCache.
     if (m_isAppCacheEnabled)
         return;
 
+    // http://crbug.com/434230 Disable preload for documents with CSP <meta> tags
+    if (m_isCSPEnabled)
+        return;
+
     switch (token.type()) {
     case HTMLToken::Character: {
         if (!m_inStyle)
             return;
         m_cssScanner.scan(token.data(), source, requests);
         return;
     }
     case HTMLToken::EndTag: {
         const StringImpl* tagImpl = tagImplFor(token.data());
         if (match(tagImpl, templateTag)) {
@@ skipping 27 matching lines @@
             // The first <base> element is the one that wins.
             if (!m_predictedBaseElementURL.isEmpty())
                 return;
             updatePredictedBaseURL(token);
             return;
         }
         if (match(tagImpl, htmlTag) && token.getAttributeItem(manifestAttr)) {
             m_isAppCacheEnabled = true;
             return;
         }
+        if (match(tagImpl, metaTag)) {
+            const typename Token::Attribute* equivAttribute = token.getAttributeItem(http_equivAttr);
+            if (equivAttribute && equalIgnoringCase(String(equivAttribute->value), "content-security-policy")) {
+                m_isCSPEnabled = true;
+                return;
+            }
+        }
 
         if (RuntimeEnabledFeatures::pictureEnabled() && (match(tagImpl, pictureTag))) {
             m_inPicture = true;
             m_pictureSourceURL = String();
             return;
         }
 
         StartTagScanner scanner(tagImpl, m_mediaValues);
         scanner.processAttributes(token.attributes());
         if (m_inPicture)
@@ skipping 48 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);
 }
 
 }