Remove _WorkerStub hack to make benefit closing an isolate.

dart/tests/isolate/isolate_stress_test.dart

+// Copyright (c) 2013, 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.
+
+// This test creates a lot of isolates.  This is meant to exhaust
+// resources if the isolates aren't closed correctly (which happened
+// in dart2js).
+
+import 'dart:async';
+import 'dart:html';
+import 'dart:isolate';
+
+// TODO(ahe): Remove dependency on unittest when tests are wrapperless.
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+
+const bool IS_UNITTEST = true;
+
+worker() {
+  port.receive((String uri, SendPort replyTo) {
+    replyTo.send('Hello from Worker');
+    port.close();
+  });
+}
+
+main() {
+  useHtmlConfiguration();
+  try {
+    // Create a Worker to confuse broken isolate implementation in dart2js.
+    new Worker('data:application/javascript,').terminate();
+  } catch (e) {
+    // Ignored.
+  }
+  var doneClosure;
+  int isolateCount = 0;
+  spawnMany(reply) {
+    if (reply != 'Hello from Worker') {
+      throw new Exception('Unexpected reply from worker: $reply');
+    }
+    if (++isolateCount > 200) {
+      if (IS_UNITTEST) {
+        doneClosure();
+      } else {
+        port.close();
+        window.postMessage('unittest-suite-done', '*');
+      }
+      return;
+    }
+    spawnFunction(worker).call('').then(spawnMany);
+    print('isolateCount = $isolateCount');
+  }
+
+  if (IS_UNITTEST) {
+    test('stress test', () {
+      spawnMany('Hello from Worker');
+      doneClosure = expectAsync0(() {});
+    });
+  } else {
+    spawnMany('Hello from Worker');
+    window.postMessage('unittest-suite-wait-for-done', '*');
+  }
+}