workers: Move ownership of WebThread from WorkerThread

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 39 matching lines @@
 class WorkerSharedTimer;
 class WorkerThreadShutdownFinishTask;
 class WorkerThreadStartupData;
 class WorkerThreadTask;
 
 enum WorkerThreadStartMode {
     DontPauseWorkerGlobalScopeOnStart,
     PauseWorkerGlobalScopeOnStart
 };
 
+// TODO(sadrul): Rename to WorkerScript.
 class CORE_EXPORT WorkerThread : public RefCounted<WorkerThread> {
 public:
     virtual ~WorkerThread();
 
     virtual void start();
     virtual void stop();
 
-    virtual PassOwnPtr<WebThreadSupportingGC> createWebThreadSupportingGC();
+    // Returns the thread this worker runs on. Some implementations can create
+    // a new thread on the first call (e.g. shared, dedicated workers), whereas
+    // some implementations can use an existing thread that is already being
+    // used by other workers (e.g.  compositor workers).
+    virtual WebThreadSupportingGC& backingThread() = 0;
+
     virtual void didStartRunLoop();
     virtual void didStopRunLoop();
 
     v8::Isolate* isolate() const { return m_isolate; }
 
     // Can be used to wait for this worker thread to shut down.
     // (This is signalled on the main thread, so it's assumed to be waited on the worker context thread)
     WebWaitableEvent* shutdownEvent() { return m_shutdownEvent.get(); }
 
     WebWaitableEvent* terminationEvent() { return m_terminationEvent.get(); }
     void terminateAndWait();
     static void terminateAndWaitForAllWorkers();
 
-    bool isCurrentThread() const;
+    bool isCurrentThread();
     WorkerLoaderProxy* workerLoaderProxy() const
     {
         RELEASE_ASSERT(m_workerLoaderProxy);
         return m_workerLoaderProxy.get();
     }
 
     WorkerReportingProxy& workerReportingProxy() const { return m_workerReportingProxy; }
 
     void postTask(const WebTraceLocation&, PassOwnPtr<ExecutionContextTask>);
     void postDebuggerTask(const WebTraceLocation&, PassOwnPtr<ExecutionContextTask>);
 
     enum WaitMode { WaitForMessage, DontWaitForMessage };
     MessageQueueWaitResult runDebuggerTask(WaitMode = WaitForMessage);
 
     // These methods should be called if the holder of the thread is
     // going to call runDebuggerTask in a loop.
     void willEnterNestedLoop();
     void didLeaveNestedLoop();
 
     WorkerGlobalScope* workerGlobalScope() const { return m_workerGlobalScope.get(); }
     bool terminated();
 
     // Number of active worker threads.
     static unsigned workerThreadCount();
 
-    PlatformThreadId platformThreadId() const;
+    PlatformThreadId platformThreadId();
 
     void interruptAndDispatchInspectorCommands();
     void setWorkerInspectorController(WorkerInspectorController*);
 
 protected:
-    WorkerThread(const char* threadName, PassRefPtr<WorkerLoaderProxy>, WorkerReportingProxy&, PassOwnPtr<WorkerThreadStartupData>);
+    WorkerThread(PassRefPtr<WorkerLoaderProxy>, WorkerReportingProxy&, PassOwnPtr<WorkerThreadStartupData>);
 
     // Factory method for creating a new worker context for the thread.
     virtual PassRefPtrWillBeRawPtr<WorkerGlobalScope> createWorkerGlobalScope(PassOwnPtr<WorkerThreadStartupData>) = 0;
 
     virtual void postInitialize() { }
 
     virtual v8::Isolate* initializeIsolate();
     virtual void willDestroyIsolate();
     virtual void destroyIsolate();
     virtual void terminateV8Execution();
 
 private:
     friend class WorkerSharedTimer;
     friend class WorkerThreadShutdownFinishTask;
 
     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);
 
-    const char* m_threadName;
+    bool m_started;
     bool m_terminated;
     MessageQueue<WorkerThreadTask> m_debuggerMessageQueue;
     OwnPtr<WebThread::TaskObserver> m_microtaskRunner;
 
     RefPtr<WorkerLoaderProxy> m_workerLoaderProxy;
     WorkerReportingProxy& m_workerReportingProxy;
 
     RefPtrWillBePersistent<WorkerInspectorController> m_workerInspectorController;
     Mutex m_workerInspectorControllerMutex;
 
     Mutex m_threadCreationMutex;
     RefPtrWillBePersistent<WorkerGlobalScope> m_workerGlobalScope;
     OwnPtr<WorkerThreadStartupData> m_startupData;
 
     v8::Isolate* m_isolate;
     OwnPtr<V8IsolateInterruptor> m_interruptor;
 
     // Used to signal thread shutdown.
     OwnPtr<WebWaitableEvent> m_shutdownEvent;
 
     // Used to signal thread termination.
     OwnPtr<WebWaitableEvent> m_terminationEvent;
-
-    // FIXME: This has to be last because of crbug.com/401397 - the
-    // WorkerThread might get deleted before it had a chance to properly
-    // shut down. By deleting the WebThread first, we can guarantee that
-    // no pending tasks on the thread might want to access any of the other
-    // members during the WorkerThread's destruction.
-    OwnPtr<WebThreadSupportingGC> m_thread;
 };
 
 } // namespace blink
 
 #endif // WorkerThread_h