Remove the concept of a cleanup task

Source/core/workers/WorkerThread.h

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 28 matching lines @@
 #include "wtf/OwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include <v8.h>
 
 namespace blink {
 
 class WebWaitableEvent;
 class WorkerGlobalScope;
 class WorkerInspectorController;
+class WorkerMicrotaskRunner;
 class WorkerReportingProxy;
 class WorkerSharedTimer;
-class WorkerThreadShutdownFinishTask;
 class WorkerThreadStartupData;
 class WorkerThreadTask;
 
 enum WorkerThreadStartMode {
     DontPauseWorkerGlobalScopeOnStart,
     PauseWorkerGlobalScopeOnStart
 };
 
 // TODO(sadrul): Rename to WorkerScript.
 class CORE_EXPORT WorkerThread : public RefCounted<WorkerThread> {
@@ skipping 61 matching lines @@
 
     virtual void postInitialize() { }
 
     virtual v8::Isolate* initializeIsolate();
     virtual void willDestroyIsolate();
     virtual void destroyIsolate();
     virtual void terminateV8Execution();
 
 private:
     friend class WorkerSharedTimer;
-    friend class WorkerThreadShutdownFinishTask;
+    friend class WorkerMicrotaskRunner;
 
     void stopInShutdownSequence();
     void stopInternal();
 
     void initialize();
     void cleanup();
     void idleHandler();
     void postDelayedTask(PassOwnPtr<ExecutionContextTask>, long long delayMs);
     void postDelayedTask(const WebTraceLocation&, PassOwnPtr<ExecutionContextTask>, long long delayMs);
 
@@ skipping 18 matching lines @@
     // Used to signal thread shutdown.
     OwnPtr<WebWaitableEvent> m_shutdownEvent;
 
     // Used to signal thread termination.
     OwnPtr<WebWaitableEvent> m_terminationEvent;
 };
 
 } // namespace blink
 
 #endif // WorkerThread_h