Force synchronized parser for substitute main resource load marked forceSynchronousLoad.

Before this CL, synchronized parsing for forceSynchronousLoad
substituteData was not enforced. The flag was simply ignored in parsing
code path.

This bug has not surfaced because all substituteData which required
synchronized loading were used against about:blank URL, and
HTMLDocumentParserOptions had a special casing that about:blank urls
required synchronous parsing.

This CL explicitly enforces synchronous parse for forceSynchronousLoad
substituteData, so that flag is actually used.
This is also a step toward removing special casing against about:black
URL in HTMLDocumentParser.

BUG=421289

Review URL: https://codereview.chromium.org/646913002

git-svn-id: svn://svn.chromium.org/blink/trunk@183570 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/loader/DocumentLoader.cpp

@@ -521,6 +521,10 @@ void DocumentLoader::ensureWriter(const AtomicString& mimeType, const KURL& over
 
     m_writer = createWriterFor(0, init, mimeType, encoding, false);
     m_writer->setDocumentWasLoadedAsPartOfNavigation();
+
+    if (m_substituteData.isValid() && m_substituteData.forceSynchronousLoad())
+        m_writer->forceSynchronousParse();
+
     // This should be set before receivedFirstData().
     if (!overridingURL.isEmpty())
         m_frame->document()->setBaseURLOverride(overridingURL);

third_party/WebKit/Source/core/loader/DocumentWriter.cpp

@@ -56,6 +56,7 @@ DocumentWriter::DocumentWriter(Document* document, const AtomicString& mimeType,
     // original parser, even if the document acquires a new parser (e.g., via
     // document.open).
     , m_parser(m_document->implicitOpen())
+    , m_forcedSynchronousParse(false)
 {
     if (m_document->frame()) {
         if (FrameView* view = m_document->frame()->view())
@@ -73,6 +74,15 @@ void DocumentWriter::trace(Visitor* visitor)
     visitor->trace(m_parser);
 }
 
+void DocumentWriter::forceSynchronousParse()
+{
+    ASSERT(!m_forcedSynchronousParse);
+
+    ASSERT(m_parser);
+    m_parser->pinToMainThread();
+    m_forcedSynchronousParse = true;
+}
+
 void DocumentWriter::appendReplacingData(const String& source)
 {
     m_document->setCompatibilityMode(Document::NoQuirksMode);
@@ -80,7 +90,8 @@ void DocumentWriter::appendReplacingData(const String& source)
     // FIXME: This should call DocumentParser::appendBytes instead of append
     // to support RawDataDocumentParsers.
     if (DocumentParser* parser = m_document->parser()) {
-        parser->pinToMainThread();
+        if (!m_forcedSynchronousParse)
+            forceSynchronousParse();
         // Because we're pinned to the main thread we don't need to worry about
         // passing ownership of the source string.
         parser->append(source.impl());

third_party/WebKit/Source/core/loader/DocumentWriter.h

@@ -49,6 +49,7 @@ public:
 
     void end();
 
+    void forceSynchronousParse();
     void addData(const char* bytes, size_t length);
 
     const AtomicString& mimeType() const { return m_decoderBuilder.mimeType(); }
@@ -68,6 +69,7 @@ private:
     TextResourceDecoderBuilder m_decoderBuilder;
 
     RefPtrWillBeMember<DocumentParser> m_parser;
+    bool m_forcedSynchronousParse;
 };
 
 } // namespace blink