Remove the Dromaeo and TodoMVC samples.

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

-library todomvc.web.elements.td_item;
-
-import 'dart:html';
-import 'package:polymer/polymer.dart';
-import 'td_model.dart';
-
-@CustomTag('td-item')
-class TodoItem extends LIElement with Polymer, Observable {
-  @published bool editing = false;
-  @published Todo item;
-
-  factory TodoItem() => new Element.tag('li', 'td-item');
-  TodoItem.created() : super.created() { polymerCreated(); }
-
-  editAction() {
-    editing = true;
-    // schedule focus for the end of microtask, when the input will be visible
-    async((_) => $['edit'].focus());
-  }
-
-  commitAction() {
-    if (editing) {
-      editing = false;
-      item.title = item.title.trim();
-      if (item.title == '') {
-        destroyAction();
-      }
-      fire('td-item-changed');
-    }
-  }
-
-  cancelAction() {
-    editing = false;
-  }
-
-  itemChangeAction() {
-    // TODO(jmesserly): asyncFire is needed because "click" fires before
-    // "item.checked" is updated on Firefox. Need to check Polymer.js.
-    asyncFire('td-item-changed');
-  }
-
-  destroyAction() {
-    fire('td-destroy-item', detail: item);
-  }
-}