Update TodoMVC based on https://github.com/polymer/todomvc

samples/third_party/todomvc/web/lib-elements/simple_router.dart

+// Copyright 2013 The Polymer Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+library todomvc.web.lib_elements.simple_router;
+
+import 'dart:async';
+import 'dart:html';
+import 'package:polymer/polymer.dart';
+
+// A very simple router for TodoMVC. Real app should use package:route, but it
+// does not currently support Shadow DOM.
+@CustomTag('simple-router')
+class SimpleRouter extends PolymerElement {
+  @published String route = '';
+
+  StreamSubscription _sub;
+
+  factory SimpleRouter() => new Element.tag('simple-router');
+  SimpleRouter.created() : super.created();
+
+  enteredView() {
+    _sub = windowLocation.changes.listen((_) {
+      var hash = window.location.hash;
+      if (hash.startsWith('#/')) hash = hash.substring(2);
+      // TODO(jmesserly): empty string is not triggering a call to TodoList
+      // routeChanged after deployment. Use 'all' as a workaround.
+      if (hash == '') hash = 'all';
+      route = hash;
+    });
+  }
+
+  leftView() {
+    _sub.cancel();
+  }
+
+  routeChanged() {
+    fire('route', detail: route);
+  }
+}