[d8 Workers] Fix bug creating Worker during main thread termination

src/d8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_D8_H_
 #define V8_D8_H_
 
 #ifndef V8_SHARED
 #include "src/allocation.h"
 #include "src/hashmap.h"
@@ skipping 203 matching lines @@
   base::Mutex mutex_;
   i::List<SerializationData*> data_;
 };
 
 
 class Worker {
  public:
   Worker();
   ~Worker();
 
-  void StartExecuteInThread(Isolate* isolate, const char* script);
+  // Run the given script on this Worker. This function should only be called
+  // once, and should only be called by the thread that created the Worker.
+  void StartExecuteInThread(const char* script);
   // Post a message to the worker's incoming message queue. The worker will
   // take ownership of the SerializationData.
+  // This function should only be called by the thread that created the Worker.
   void PostMessage(SerializationData* data);
   // Synchronously retrieve messages from the worker's outgoing message queue.
   // If there is no message in the queue, block until a message is available.
   // If there are no messages in the queue and the worker is no longer running,
   // return nullptr.
+  // This function should only be called by the thread that created the Worker.
   SerializationData* GetMessage();
   // Terminate the worker's event loop. Messages from the worker that have been
   // queued can still be read via GetMessage().
+  // This function can be called by any thread.
   void Terminate();
   // Terminate and join the thread.
+  // This function can be called by any thread.
   void WaitForThread();
 
  private:
   class WorkerThread : public base::Thread {
    public:
     explicit WorkerThread(Worker* worker)
         : base::Thread(base::Thread::Options("WorkerThread")),
           worker_(worker) {}
 
     virtual void Run() { worker_->ExecuteInThread(); }
 
    private:
     Worker* worker_;
   };
 
-  enum State {
-    IDLE,       // The worker thread hasn't been started yet
-    RUNNING,    // The worker thread is running and hasn't been terminated
-    TERMINATED  // The worker thread has been terminated and will soon finish
-  };
-
   void ExecuteInThread();
   static void PostMessageOut(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   base::Semaphore in_semaphore_;
   base::Semaphore out_semaphore_;
   SerializationDataQueue in_queue_;
   SerializationDataQueue out_queue_;
   base::Thread* thread_;
   char* script_;
-  base::Atomic32 state_;
-  base::Atomic32 join_called_;
+  base::Atomic32 running_;
 };
 #endif  // !V8_SHARED
 
 
 class ShellOptions {
  public:
   ShellOptions()
       : script_executed(false),
         last_run(true),
         send_idle_notification(false),
@@ skipping 189 matching lines @@
   static void RunShell(Isolate* isolate);
   static bool SetOptions(int argc, char* argv[]);
   static Local<ObjectTemplate> CreateGlobalTemplate(Isolate* isolate);
 };
 
 
 }  // namespace v8
 
 
 #endif  // V8_D8_H_