Centralized event streams

runtime/observatory/tests/observatory_ui/nav/menu/element_test.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.
 import 'dart:html';
 import 'package:unittest/unittest.dart';
 import 'package:observatory/src/elements/nav/menu.dart';
 
 main() {
   NavMenuElement.tag.ensureRegistration();
 
   group('instantiation', () {
     final label = 'custom-label';
     test('label', () {
-      final NavMenuElement e = new NavMenuElement(label);
+      final e = new NavMenuElement(label);
       expect(e, isNotNull, reason: 'element correctly created');
       expect(e.label, equals(label), reason: 'element correctly created');
     });
     test('not last', () {
-      final NavMenuElement e = new NavMenuElement(label, last: false);
+      final e = new NavMenuElement(label, last: false);
       expect(e, isNotNull, reason: 'element correctly created');
       expect(e.last, isFalse, reason: 'element correctly created');
     });
     test('last', () {
-      final NavMenuElement e = new NavMenuElement(label, last: true);
+      final e = new NavMenuElement(label, last: true);
       expect(e, isNotNull, reason: 'element correctly created');
       expect(e.last, isTrue, reason: 'element correctly created');
     });
   });
   group('elements', () {
     test('created', () async {
       final label = 'custom-label';
-      final NavMenuElement e = new NavMenuElement(label);
+      final e = new NavMenuElement(label);
       document.body.append(e);
       await e.onRendered.first;
       expect(e.shadowRoot.children.length, isNonZero, reason: 'has elements');
       expect(e.shadowRoot.querySelector('content'), isNotNull,
                                                  reason: 'has content elements');
       e.remove();
       await e.onRendered.first;
       expect(e.shadowRoot.children.length, isZero, reason: 'is empty');
     });
     test('react to label change', () async {
       final label1 = 'custom-label-1';
       final label2 = 'custom-label-2';
-      final NavMenuElement e = new NavMenuElement(label1);
+      final e = new NavMenuElement(label1);
       document.body.append(e);
       await e.onRendered.first;
       expect(e.shadowRoot.innerHtml.contains(label1), isTrue);
       expect(e.shadowRoot.innerHtml.contains(label2), isFalse);
       e.label = label2;
       await e.onRendered.first;
       expect(e.shadowRoot.innerHtml.contains(label1), isFalse);
       expect(e.shadowRoot.innerHtml.contains(label2), isTrue);
       e.remove();
       await e.onRendered.first;
     });
     test('react to last change', () async {
       final label = 'custom-label';
-      final NavMenuElement e = new NavMenuElement(label, last: false);
+      final e = new NavMenuElement(label, last: false);
       document.body.append(e);
       await e.onRendered.first;
       expect(e.shadowRoot.innerHtml.contains('>'), isTrue);
       e.last = true;
       await e.onRendered.first;
       expect(e.shadowRoot.innerHtml.contains('>'), isFalse);
       e.last = false;
       await e.onRendered.first;
       expect(e.shadowRoot.innerHtml.contains('>'), isTrue);
       e.remove();
       await e.onRendered.first;
     });
   });
 }