Renderer-side changes for NoState Prefetch

third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.cpp

Index: third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.cpp b/third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.cpp
index 33b3cf558eb3c42d2b2fe90899045a4251ef2de0..22b910e2d985864a5bb4053b57238f5de536bad9 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.cpp
+++ b/third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.cpp
@@ -130,6 +130,9 @@ HTMLDocumentParser::HTMLDocumentParser(Document& document, ParserContentPolicy c
     , m_triedLoadingLinkHeaders(false)
 {
     ASSERT(shouldUseThreading() || (m_token && m_tokenizer));
+    // Threading is not allowed in prefetch mode.
+    DCHECK(!document.isPrefetchOnly() || !shouldUseThreading());
+
     ThreadState::current()->registerPreFinalizer(this);
 }
 
@@ -797,6 +800,18 @@ void HTMLDocumentParser::append(const String& inputSource)
     TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("blink.debug"), "HTMLDocumentParser::append", "size", inputSource.length());
     const SegmentedString source(inputSource);
 
+    if (document()->isPrefetchOnly()) {
+        if (!m_preloadScanner)
+            m_preloadScanner = createPreloadScanner();
+
+        m_preloadScanner->appendToEnd(source);
+        // TODO(droger): Set the LOAD_PREFETCH flags on the requests.
+        m_preloadScanner->scanAndPreload(m_preloader.get(), document()->validBaseElementURL(), nullptr);
+
+        // Return after the preload scanner, do not actually parse the document.
+        return;
+    }
+
     if (m_preloadScanner) {
         if (m_input.current().isEmpty() && !isWaitingForScripts()) {
             // We have parsed until the end of the current input and so are now moving ahead of the preload scanner.