Reland: Make the HTMLDocumentParser yield more aggressively

Source/core/html/parser/HTMLDocumentParser.cpp

Index: Source/core/html/parser/HTMLDocumentParser.cpp
diff --git a/Source/core/html/parser/HTMLDocumentParser.cpp b/Source/core/html/parser/HTMLDocumentParser.cpp
index 1d349669659c14a25a20a5e5a2b2e425478d756a..6cc075f65e96951c156dc0cb91c14dc6432e219a 100644
--- a/Source/core/html/parser/HTMLDocumentParser.cpp
+++ b/Source/core/html/parser/HTMLDocumentParser.cpp
@@ -328,25 +328,28 @@ void HTMLDocumentParser::didReceiveParsedChunkFromBackgroundParser(PassOwnPtr<Pa
 {
     TRACE_EVENT0("blink", "HTMLDocumentParser::didReceiveParsedChunkFromBackgroundParser");
 
-    // alert(), runModalDialog, and the JavaScript Debugger all run nested event loops
-    // which can cause this method to be re-entered. We detect re-entry using
-    // hasActiveParser(), save the chunk as a speculation, and return.
-    if (isWaitingForScripts() || !m_speculations.isEmpty() || document()->activeParserCount() > 0 || m_tasksWereSuspended || isScheduledForResume()) {
-        if (m_tasksWereSuspended)
-            m_parserScheduler->forceResumeAfterYield();
-        m_preloader->takeAndPreload(chunk->preloads);
-        m_speculations.append(chunk);
+    if (!isParsing())
         return;
-    }
 
-    // processParsedChunkFromBackgroundParser can cause this parser to be detached from the Document,
-    // but we need to ensure it isn't deleted yet.
-    RefPtrWillBeRawPtr<HTMLDocumentParser> protect(this);
+    // ApplicationCache needs to be initialized before issuing preloads.
+    // We suspend preload until HTMLHTMLElement is inserted and
+    // ApplicationCache is initialized.
+    if (!document()->documentElement()) {
+        for (auto& request : chunk->preloads)
+            m_queuedPreloads.append(request.release());
+    } else {
+        ASSERT(m_queuedPreloads.isEmpty());

[tyoshino (SeeGerritForStatus), 2014/12/04 06:48:21]

please write the reason that we're sure that m_queuedPreloads is already
consumed when we arrive here.

+        m_preloader->takeAndPreload(chunk->preloads);
+    }
 
-    ASSERT(m_speculations.isEmpty());
-    chunk->preloads.clear(); // We don't need to preload because we're going to parse immediately.
     m_speculations.append(chunk);
-    pumpPendingSpeculations();
+
+    if (!isWaitingForScripts() && !isScheduledForResume()) {
+        if (m_tasksWereSuspended)
+            m_parserScheduler->forceResumeAfterYield();
+        else
+            m_parserScheduler->scheduleForResume();
+    }
 }
 
 void HTMLDocumentParser::didReceiveEncodingDataFromBackgroundParser(const DocumentEncodingData& data)
@@ -463,6 +466,9 @@ size_t HTMLDocumentParser::processParsedChunkFromBackgroundParser(PassOwnPtr<Par
 
         constructTreeFromCompactHTMLToken(*it);
 
+        if (!m_queuedPreloads.isEmpty() && document()->documentElement())
+            m_preloader->takeAndPreload(m_queuedPreloads);
+

[tyoshino (SeeGerritForStatus), 2014/12/04 06:48:21]

before this CL we were calling chunk->preloads.clear(). Now, you're calling
takeAndPreload(). If this is intentional change, please write the purpose in the
CL description.

         if (isStopped())
             break;