Enables clean VM shutdown.

runtime/vm/message_handler.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_MESSAGE_HANDLER_H_
 #define VM_MESSAGE_HANDLER_H_
 
 #include "vm/isolate.h"
 #include "vm/message.h"
 #include "vm/os_thread.h"
@@ skipping 18 matching lines @@
 
   // Runs this message handler on the thread pool.
   //
   // Before processing messages, the optional StartFunction is run.
   //
   // A message handler will run until it terminates either normally or
   // abnormally.  Normal termination occurs when the message handler
   // no longer has any live ports.  Abnormal termination occurs when
   // HandleMessage() indicates that an error has occurred during
   // message processing.
-  void Run(ThreadPool* pool,
-           StartCallback start_callback,
+  void Run(StartCallback start_callback,
            EndCallback end_callback,
            CallbackData data);
 
   // Handles the next message for this message handler.  Should only
   // be used when not running the handler on the thread pool (via Run
   // or RunBlocking).
   //
   // Returns true on success.
   bool HandleNextMessage();
 
@@ skipping 149 matching lines @@
   MessageQueue* oob_queue_;
   // This flag is not thread safe and can only reliably be accessed on a single
   // thread.
   bool oob_message_handling_allowed_;
   intptr_t live_ports_;  // The number of open ports, including control ports.
   intptr_t paused_;  // The number of pause messages received.
   bool pause_on_start_;
   bool pause_on_exit_;
   bool paused_on_start_;
   bool paused_on_exit_;
-  ThreadPool* pool_;
+  bool running_;
   ThreadPool::Task* task_;
   StartCallback start_callback_;
   EndCallback end_callback_;
   CallbackData callback_data_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageHandler);
 };
 
 }  // namespace dart
 
 #endif  // VM_MESSAGE_HANDLER_H_