Expose Zones.

tests/lib/async/catch_errors.dart

 library catch_errors;
 
 import 'dart:async';
 
 Stream catchErrors(void body()) {
   StreamController controller;
 
   bool onError(e) {
     controller.add(e);
     return true;
   }
 
-  void onDone() {
-    controller.close();
-  }
-
   void onListen() {
-    runZonedExperimental(body, onError: onError, onDone: onDone);
+    runZoned(body, onError: onError);
   }
 
   controller = new StreamController(onListen: onListen);
   return controller.stream;
 }
-
-Future waitForCompletion(void body()) {
-  Completer completer = new Completer.sync();
-  runZonedExperimental(body, onDone: completer.complete);
-  return completer.future;
-}