Clean VM thread shutdown:

runtime/vm/custom_isolate_test.cc

 // 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.
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 
 #include "vm/unit_test.h"
 
 // Custom Isolate Test.
@@ skipping 41 matching lines @@
     "  SendPort spawn();\n"
     "}\n"
     "\n"
     "isolateMain() {\n"
     "   echo('Running isolateMain');\n"
     "   mainPort.handler = (message) {\n"
     "     var data = message[0];\n"
     "     var replyTo = message[1];\n"
     "     echo('Received: $data');\n"
     "     replyTo.send(data + 1);\n"
+    "     mainPort.close();\n"
     "   };\n"
     "}\n"
     "\n"
     "main() {\n"
     "  var isolate = new CustomIsolate(\"isolateMain\");\n"
     "  var receivePort = new RawReceivePort();\n"
     "  SendPort port = isolate.spawn();\n"
     "  port.send([42, receivePort.sendPort]);\n"
     "  receivePort.handler = (message) {\n"
     "    receivePort.close();\n"
@@ skipping 100 matching lines @@
   Dart_Handle result;
 
   Dart_Handle lib = Dart_LookupLibrary(NewString(TestCase::url()));
   EXPECT_VALID(lib);
 
   result = Dart_Invoke(lib, NewString(main_), 0, NULL);
   EXPECT_VALID(result);
   free(const_cast<char*>(main_));
   main_ = NULL;
 
+  Dart_SetMessageNotifyCallback(NULL);
   Dart_ExitScope();
   Dart_ExitIsolate();
 }
 
 
 // Notify an isolate of a pending message.
 class MessageEvent : public Event {
  public:
   explicit MessageEvent(Dart_Isolate isolate) : Event(isolate) {}
 
   ~MessageEvent() {
   }
 
   virtual void Process();
 };
 
 
 void MessageEvent::Process() {
   OS::Print("$$ MessageEvent with isolate(%p)\n", isolate());
   Dart_EnterIsolate(isolate());
   Dart_EnterScope();
 
   Dart_Handle result = Dart_HandleMessage();
   EXPECT_VALID(result);
 
   if (!Dart_HasLivePorts()) {
     OS::Print("<< Shutting down isolate(%p)\n", isolate());
     event_queue->RemoveEventsForIsolate(isolate());
+    Dart_SetMessageNotifyCallback(NULL);
     Dart_ShutdownIsolate();
   } else {
     Dart_ExitScope();
     Dart_ExitIsolate();
   }
   ASSERT(Dart_CurrentIsolate() == NULL);
 }
 
 
 static void NotifyMessage(Dart_Isolate dest_isolate) {
@@ skipping 123 matching lines @@
   while (event) {
     event->Process();
     delete event;
     event = event_queue->Get();
   }
   OS::Print("-- Finished event loop --\n");
   EXPECT_STREQ("Received: 43", saved_echo);
   free(const_cast<char*>(saved_echo));
 
   delete event_queue;
+  event_queue = NULL;
 }
 
 }  // namespace dart