Centralized event streams

runtime/observatory/tests/observatory_ui/mocks/objects/notification.dart

 // Copyright (c) 2016, 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
+// BSD-style license that can be found in the LICENSE file.
 
 part of mocks;
 
 class ExceptionNotificationMock implements M.ExceptionNotification {
   final Exception exception;
   final StackTrace stacktrace;
   const ExceptionNotificationMock({this.exception, this.stacktrace});
 }
 
 class EventNotificationMock implements M.EventNotification {
   final M.Event event;
   const EventNotificationMock({this.event});
 }