Turn DocumentParser::pinToMainThread into a cleaner api

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 63cb1e518c441db49e3ef02308e29485cf4d1bf2..449dab76957d721cd8d514cdc75ea4f188da85fa 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -508,6 +508,7 @@ Document::Document(const DocumentInit& initializer, DocumentClassFlags documentC
     , m_didAssociateFormControlsTimer(this, &Document::didAssociateFormControlsTimerFired)
     , m_hasViewportUnits(false)
     , m_styleRecalcElementCounter(0)
+    , m_backgroundParsingPolicy(AllowAsynchronousParsing)
 {
     if (m_frame) {
         ASSERT(m_frame->page());
@@ -1233,11 +1234,6 @@ KURL Document::baseURI() const
 void Document::setContent(const String& content)
 {
     open();
-    // FIXME: This should probably use insert(), but that's (intentionally)
-    // not implemented for the XML parser as it's normally synonymous with
-    // document.write(). append() will end up yielding, but close() will
-    // pump the tokenizer syncrhonously and finish the parse.
-    m_parser->pinToMainThread();

[kbalazs, 2014/12/05 23:37:57]

Note that this called XMLDocumentParser::pinToMainThread which is noop.

About the yeilding mentioned in the comment that does not happen for synchronous
parsing which is enforced by using open() instead of implicitOpen(). And this
should not use insert for sure because insert is only for document.write.

     m_parser->append(content.impl());
     close();
 }
@@ -2288,7 +2284,7 @@ PassRefPtrWillBeRawPtr<DocumentParser> Document::createParser()
 {
     if (isHTMLDocument()) {
         bool reportErrors = InspectorInstrumentation::collectingHTMLParseErrors(page());
-        return HTMLDocumentParser::create(toHTMLDocument(*this), reportErrors);
+        return HTMLDocumentParser::create(toHTMLDocument(*this), reportErrors, m_backgroundParsingPolicy);
     }
     // FIXME: this should probably pass the frame instead
     return XMLDocumentParser::create(*this, view());
@@ -2335,6 +2331,8 @@ void Document::open(Document* ownerDocument, ExceptionState& exceptionState)
             m_frame->loader().stopAllLoaders();
     }
 
+    forceSynchronousParsing();

[kbalazs, 2014/12/05 23:37:57]

This is in open() (not obvious from the context).

+
     removeAllEventListenersRecursively();
     implicitOpen();
     if (ScriptableDocumentParser* parser = scriptableDocumentParser())
@@ -2346,6 +2344,12 @@ void Document::open(Document* ownerDocument, ExceptionState& exceptionState)
         m_loadEventProgress = LoadEventNotRun;
 }
 
+void Document::forceSynchronousParsing()
+{
+    ASSERT(!m_parser);
+    m_backgroundParsingPolicy = ForceSynchronousParsing;
+}
+
 void Document::detachParser()
 {
     if (!m_parser)