Reland: Make the HTMLDocumentParser yield more aggressively

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 6c988f0ff0d89fe86e5414b7b8fd28b61455bdbc..084de2ba37ccbdb11cbd84deb5ebf128ccc79851 100644
--- a/Source/core/html/parser/HTMLPreloadScanner.cpp
+++ b/Source/core/html/parser/HTMLPreloadScanner.cpp
@@ -374,6 +374,7 @@ TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassRefPtr<Med
     , m_inStyle(false)
     , m_inPicture(false)
     , m_isAppCacheEnabled(false)
+    , m_isCSPEnabled(false)
     , m_templateCount(0)
     , m_mediaValues(mediaValues)
 {
@@ -386,7 +387,7 @@ 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;
 }
 
@@ -397,6 +398,7 @@ void TokenPreloadScanner::rewindTo(TokenPreloadScannerCheckpoint 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();
@@ -419,6 +421,10 @@ void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString&
     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)
@@ -466,6 +472,13 @@ void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString&
             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;