Converted Observatory top-nav-menu element

runtime/observatory/lib/src/elements/nav/top_menu.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 'dart:async';
+import 'package:observatory/src/elements/helpers/tag.dart';
+import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
+import 'package:observatory/src/elements/nav/menu.dart';
+import 'package:observatory/src/elements/nav/menu_item.dart';
+
+class NavTopMenuElement extends HtmlElement implements Renderable {
+  static const tag = const Tag<NavTopMenuElement>('nav-top-menu',
+                     dependencies: const [NavMenuElement.tag,
+                                          NavMenuItemElement.tag]);
+
+  RenderingScheduler _r;
+
+  Stream<RenderedEvent<NavTopMenuElement>> get onRendered => _r.onRendered;
+
+  bool _last;
+  bool get last => _last;
+  set last(bool value) => _last = _r.checkAndReact(_last, value);
+
+  factory NavTopMenuElement({bool last: false, RenderingQueue queue}) {
+    assert(last != null);
+    NavTopMenuElement e = document.createElement(tag.name);
+    e._r = new RenderingScheduler(e, queue: queue);
+    e._last = last;
+    return e;
+  }
+
+  NavTopMenuElement.created() : super.created() { createShadowRoot(); }
+
+  @override
+  void attached() {
+    super.attached();
+    _r.enable();
+  }
+
+  @override
+  void detached() {
+    super.detached();
+    _r.disable(notify: true);
+    shadowRoot.children = [];
+  }
+
+  void render() {
+    shadowRoot.children = [
+      new NavMenuElement('Observatory', link: '/vm', last: last,
+                         queue: _r.queue)
+        ..children = [
+          new NavMenuItemElement('Connect to a VM', link: '/vm-connect',
+                                 queue: _r.queue),
+          new ContentElement()
+        ]
+    ];
+  }
+}