Remove the Dromaeo and TodoMVC samples.

samples/third_party/todomvc_performance/web/elements/td_todos.dart

-library todomvc.web.elements.td_todos;
-
-import 'dart:html';
-import 'package:polymer/polymer.dart';
-import 'td_input.dart';
-import 'td_model.dart';
-
-@CustomTag('td-todos')
-class TodoList extends PolymerElement {
-  @published String modelId;
-
-  @observable TodoModel model;
-  @observable String activeRoute;
-
-  factory TodoList() => new Element.tag('td-todos');
-  TodoList.created() : super.created();
-
-  TodoInput get _newTodo => $['new-todo'];
-
-  void modelIdChanged() {
-    model = document.querySelector('#$modelId');
-  }
-
-  void routeAction(e, route) {
-    if (model != null) model.filter = route;
-
-    // TODO(jmesserly): polymer_expressions lacks boolean conversions.
-    activeRoute = (route != null && route != '') ? route : 'all';
-  }
-
-  void addTodoAction() {
-    model.newItem(_newTodo.value);
-    // when polyfilling Object.observe, make sure we update immediately
-    Observable.dirtyCheck();
-    _newTodo.value = '';
-  }
-
-  void cancelAddTodoAction() {
-    _newTodo.value = '';
-  }
-
-  void itemChangedAction() {
-    if (model != null) model.itemsChanged();
-  }
-
-  void destroyItemAction(e, detail) {
-    model.destroyItem(detail);
-  }
-
-  void toggleAllCompletedAction(e, detail, sender) {
-    model.setItemsCompleted(sender.checked);
-  }
-
-  void clearCompletedAction() {
-    model.clearItems();
-  }
-
-  // TODO(jmesserly): workaround for HTML Imports not setting correct baseURI
-  String get baseUri =>
-      declaration.element.ownerDocument == document ? '../' : '';
-}