move polymer.dart into dart svn

samples/third_party/todomvc/web/app.dart

+// Copyright (c) 2013, 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.
+
+library app;
+
+import 'dart:html';
+import 'package:polymer/polymer.dart';
+import 'model.dart';
+
+@CustomTag("todo-app")
+class TodoApp extends PolymerElement with ObservableMixin {
+  @observable AppModel app;
+  bool get applyAuthorStyles => true;
+
+  void created() {
+    super.created();
+    app = appModel;
+  }
+
+  void addTodo(Event e) {
+    e.preventDefault(); // don't submit the form
+    var input = getShadowRoot('todo-app').query('#new-todo');
+    if (input.value == '') return;
+    app.todos.add(new Todo(input.value));
+    input.value = '';
+  }
+
+  void clear() => app.clearDone();
+}