Properly suspend HTMLDocumentParser

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 5e89dc7c97a5cbb5cd0efdcf1bac319f77b55eb2..709f7085ed0f49fabc007b909157110ccaced13a 100644
--- a/Source/core/html/parser/HTMLDocumentParser.cpp
+++ b/Source/core/html/parser/HTMLDocumentParser.cpp
@@ -116,6 +116,7 @@ HTMLDocumentParser::HTMLDocumentParser(HTMLDocument& document, bool reportErrors
     , m_isPinnedToMainThread(false)
     , m_endWasDelayed(false)
     , m_haveBackgroundParser(false)
+    , m_tasksWereSuspended(false)
     , m_pumpSessionNestingLevel(0)
 {
     ASSERT(shouldUseThreading() || (m_token && m_tokenizer));
@@ -134,6 +135,7 @@ HTMLDocumentParser::HTMLDocumentParser(DocumentFragment* fragment, Element* cont
     , m_isPinnedToMainThread(true)
     , m_endWasDelayed(false)
     , m_haveBackgroundParser(false)
+    , m_tasksWereSuspended(false)
     , m_pumpSessionNestingLevel(0)
 {
     ASSERT(!shouldUseThreading());
@@ -334,7 +336,9 @@ void HTMLDocumentParser::didReceiveParsedChunkFromBackgroundParser(PassOwnPtr<Pa
     // 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) {
+    if (isWaitingForScripts() || !m_speculations.isEmpty() || document()->activeParserCount() > 0 || m_tasksWereSuspended) {
+        if (m_tasksWereSuspended)
+            m_parserScheduler->forceResumeAfterYield();
         m_preloader->takeAndPreload(chunk->preloads);
         m_speculations.append(chunk);
         return;
@@ -1003,12 +1007,16 @@ void HTMLDocumentParser::parseDocumentFragment(const String& source, DocumentFra
 
 void HTMLDocumentParser::suspendScheduledTasks()
 {
+    ASSERT(!m_tasksWereSuspended);
+    m_tasksWereSuspended = true;
     if (m_parserScheduler)
         m_parserScheduler->suspend();
 }
 
 void HTMLDocumentParser::resumeScheduledTasks()
 {
+    ASSERT(m_tasksWereSuspended);
+    m_tasksWereSuspended = false;
     if (m_parserScheduler)
         m_parserScheduler->resume();
 }