Defer late and async scripts

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 1b21bc89b4408a9bbe189b2d614297b7651b7a3c..08fe987f5d53ccd22b4c15b0022c7adf7062710d 100644
--- a/Source/core/html/parser/HTMLPreloadScanner.cpp
+++ b/Source/core/html/parser/HTMLPreloadScanner.cpp
@@ -111,6 +111,7 @@ public:
         , m_sourceSize(0)
         , m_sourceSizeSet(false)
         , m_isCORSEnabled(false)
+        , m_execAsync(false)
         , m_allowCredentials(DoNotAllowStoredCredentials)
         , m_mediaValues(mediaValues)
     {
@@ -170,6 +171,7 @@ public:
         if (isCORSEnabled())
             request->setCrossOriginEnabled(allowStoredCredentials());
         request->setCharset(charset());
+        request->setExecAsync(m_execAsync);
         return request.release();
     }
 
@@ -182,6 +184,10 @@ private:
             setUrlToLoad(attributeValue, DisallowURLReplacement);
         else if (match(attributeName, crossoriginAttr))
             setCrossOriginAllowed(attributeValue);
+        else if (match(attributeName, asyncAttr))
+            setExecAsync(true);
+        else if (match(attributeName, deferAttr))
+            setExecAsync(true);
     }
 
     template<typename NameType>
@@ -337,6 +343,16 @@ private:
             m_allowCredentials = DoNotAllowStoredCredentials;
     }
 
+    void setExecAsync(const bool execAsync)
+    {
+        m_execAsync = execAsync;
+    }
+
+    bool execAsync() const
+    {
+        return m_execAsync;
+    }
+
     const StringImpl* m_tagImpl;
     String m_urlToLoad;
     ImageCandidate m_srcsetImageCandidate;
@@ -349,6 +365,7 @@ private:
     unsigned m_sourceSize;
     bool m_sourceSizeSet;
     bool m_isCORSEnabled;
+    bool m_execAsync;
     StoredCredentials m_allowCredentials;
     RefPtr<MediaValues> m_mediaValues;
 };
@@ -357,6 +374,7 @@ TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassRefPtr<Med
     : m_documentURL(documentURL)
     , m_inStyle(false)
     , m_inPicture(false)
+    , m_isBeforeBody(true)
     , m_templateCount(0)
     , m_mediaValues(mediaValues)
 {
@@ -369,7 +387,7 @@ TokenPreloadScanner::~TokenPreloadScanner()
 TokenPreloadScannerCheckpoint TokenPreloadScanner::createCheckpoint()
 {
     TokenPreloadScannerCheckpoint checkpoint = m_checkpoints.size();
-    m_checkpoints.append(Checkpoint(m_predictedBaseElementURL, m_inStyle, m_templateCount));
+    m_checkpoints.append(Checkpoint(m_predictedBaseElementURL, m_inStyle, m_isBeforeBody, m_templateCount));
     return checkpoint;
 }
 
@@ -379,8 +397,10 @@ void TokenPreloadScanner::rewindTo(TokenPreloadScannerCheckpoint checkpointIndex
     const Checkpoint& checkpoint = m_checkpoints[checkpointIndex];
     m_predictedBaseElementURL = checkpoint.predictedBaseElementURL;
     m_inStyle = checkpoint.inStyle;
+    m_isBeforeBody = checkpoint.isBeforeBody;
     m_templateCount = checkpoint.templateCount;
     m_cssScanner.reset();
+    m_cssScanner.setIsBeforeBody(m_isBeforeBody);
     m_checkpoints.clear();
 }
 
@@ -433,6 +453,10 @@ void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString&
             m_inStyle = true;
             return;
         }
+        if (m_isBeforeBody && match(tagImpl, bodyTag)) {
+            m_isBeforeBody = false;
+            m_cssScanner.setIsBeforeBody(m_isBeforeBody);
+        }
         if (match(tagImpl, baseTag)) {
             // The first <base> element is the one that wins.
             if (!m_predictedBaseElementURL.isEmpty())
@@ -451,8 +475,10 @@ void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString&
         if (m_inPicture)
             scanner.handlePictureSourceURL(m_pictureSourceURL);
         OwnPtr<PreloadRequest> request = scanner.createPreloadRequest(m_predictedBaseElementURL, source);
-        if (request)
+        if (request) {
+            request->setIsBeforeBody(m_isBeforeBody);
             requests.append(request.release());
+        }
         return;
     }
     default: {