Removed polymer & mirror from Observatory

runtime/observatory/lib/src/elements/nav/menu_item_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/src/elements/helpers/tag.dart';
-import 'package:observatory/src/elements/shims/binding.dart';
-import 'package:observatory/src/elements/nav/menu_item.dart';
-
-@bindable
-class NavMenuItemElementWrapper extends HtmlElement {
-  static const binder = const Binder<NavMenuItemElementWrapper>(const {
-      'anchor': #anchor, 'link': #link
-    });
-
-  static const tag =
-    const Tag<NavMenuItemElementWrapper>('nav-menu-item');
-
-  String _anchor;
-  String _link;
-
-  String get anchor => _anchor;
-  String get link => _link;
-  
-  set anchor(String value) {
-    _anchor = value;
-    render();
-  }
-  set link(String value) {
-    _link = value;
-    render();
-  }
-
-  NavMenuItemElementWrapper.created() : super.created() {
-    binder.registerCallback(this);
-    _anchor = getAttribute('anchor');
-    _link = getAttribute('link');
-    createShadowRoot();
-    render();
-  }
-
-  @override
-  void attached() {
-    super.attached();
-    render();
-  }
-
-  void render() {
-    shadowRoot.children = [];
-    if (_anchor == null) {
-      return;
-    }
-
-    shadowRoot.children = [
-      new NavMenuItemElement(_anchor, link: '#$link',
-                                 queue: ObservatoryApplication.app.queue)
-        ..children = [new ContentElement()]
-    ];
-  }
-}