- Implement VM parts of https://codereview.chromium.org/1240743003/

tests/isolate/exit_at_spawnuri_test.dart

+// Copyright (c) 2015, 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.
+
+library exit_at_spawn;
+
+import "dart:isolate";
+import "dart:async";
+import "package:async_helper/async_helper.dart";
+import "package:expect/expect.dart";
+
+main(){
+  asyncStart();
+
+  RawReceivePort exitPort = new RawReceivePort();
+  exitPort.handler = (message) {
+    Expect.equals(null, message);
+    exitPort.close();
+    asyncEnd();
+  };
+  
+  Isolate.spawnUri(Uri.parse("exit_at_spawnuri_iso.dart"), [],
+                   null,
+                   // Setup handler as part of spawn.
+                   errorsAreFatal: false,
+                   onExit: exitPort.sendPort);
+}