Wrapping leaf nodes in non polymer elements

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 'package:observatory/app.dart';
+import 'package:observatory/service.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');
+
+  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; render();
+  }
+
+  NavVMMenuElementWrapper.created() : super.created() {
+    binder.registerCallback(this);
+    _last = getAttribute('last') != null;
+    createShadowRoot();
+    render();
+  }
+
+  @override
+  void attached() {
+    super.attached();
+    render();
+  }
+
+  void render() {
+    shadowRoot.children = [];
+    if (_vm == null || _last == null) return;
+
+    shadowRoot.children = [
+      new NavVMMenuElement(vm, last: last,
+                           queue: ObservatoryApplication.app.queue)
+        ..children = [new ContentElement()]
+    ];
+  }
+}