Task(PassRefPtr<SerializedScriptValue> message, PassOwnPtr<MessagePortChannelArray> channels, WorkerMessagingProxy* messagingProxy)          : m_message(message)          , m_channels(channels)          , m_messagingProxy(messagingProxy)      {      }        virtual void performTask(ScriptExecutionContext* scriptContext)      {          Worker* workerObject = m_messagingProxy->workerObject();          if (!workerObject