Converted Observatory vm-nav-menu element

runtime/observatory/lib/src/elements/nav/vm_menu_wrapper.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/app.dart';
+import 'package:observatory/mocks.dart';
+import 'package:observatory/models.dart' as M;
+import 'package:observatory/service.dart';
+import 'package:observatory/service_common.dart';
+import 'package:observatory/src/elements/helpers/tag.dart';
+import 'package:observatory/src/elements/shims/binding.dart';
+import 'package:observatory/src/elements/nav/vm_menu.dart';
+
+class NavVMMenuElementWrapper extends HtmlElement {
+  static final binder = new Binder<NavVMMenuElementWrapper>(
+    const [const Binding('last'), const Binding('vm')]);
+
+  static const tag = const Tag<NavVMMenuElementWrapper>('vm-nav-menu');
+
+  StreamSubscription _subscription;
+  StreamController<M.VMUpdateEvent> _updatesController =
+      new StreamController<M.VMUpdateEvent>.broadcast();
+
+  bool _last = false;
+  VM _vm;
+  bool get last => _last;
+  VM get vm => _vm;
+  set last(bool value) {
+    _last = value; render();
+  }
+  set vm(VM value) {
+    _vm = value; _detached(); _attached();
+  }
+
+  NavVMMenuElementWrapper.created() : super.created() {
+    binder.registerCallback(this);
+    _last = _getBoolAttribute('last');
+    createShadowRoot();
+    render();
+  }
+
+  @override
+  void attached() {
+    super.attached();
+    _attached();
+  }
+
+  @override
+  void detached() {
+    super.detached();
+    _detached();
+  }
+
+  void _attached() {
+    if (_vm != null) {
+      _subscription = _vm.changes.listen((_) {
+        _updatesController.add(new VMUpdateEventMock(vm: _vm));
+      });
+    }
+    render();
+  }
+
+  void _detached() {
+    if (_subscription != null) {
+      _subscription.cancel();
+      _subscription = null;
+    }
+  }
+
+  void render() {
+    shadowRoot.children = [];
+    if (_vm == null || _last == null) return;
+
+    shadowRoot.children = [
+      new NavVMMenuElement(vm, _updatesController.stream, last: last,
+          target: (vm as CommonWebSocketVM)?.target,
+          queue: ObservatoryApplication.app.queue)
+        ..children = [new ContentElement()]
+    ];
+  }
+
+  bool _getBoolAttribute(String name) {
+    final String value = getAttribute(name);
+    return !(value == null || value == 'false');
+  }
+}