Remove the concept of a cleanup task

Source/core/html/parser/HTMLParserThread.cpp

Index: Source/core/html/parser/HTMLParserThread.cpp
diff --git a/Source/core/html/parser/HTMLParserThread.cpp b/Source/core/html/parser/HTMLParserThread.cpp
index 18d8e5ea1ef7b7015848ca8124625dacc04d6b6b..b7eec5984f413a0d97da253daf62dbb54ec7f711 100644
--- a/Source/core/html/parser/HTMLParserThread.cpp
+++ b/Source/core/html/parser/HTMLParserThread.cpp
@@ -58,7 +58,7 @@ void HTMLParserThread::init()
 void HTMLParserThread::setupHTMLParserThread()
 {
     ASSERT(m_thread);
-    m_thread->attachGC();
+    m_thread->initialize();
 }
 
 void HTMLParserThread::shutdown()
@@ -74,7 +74,7 @@ void HTMLParserThread::shutdown()
 
 void HTMLParserThread::cleanupHTMLParserThread()
 {
-    m_thread->detachGC();
+    m_thread->shutdown();
 }
 
 HTMLParserThread* HTMLParserThread::shared()