Add a menu to the stocks app

sky/examples/stocks-fn/lib/stock_menu.dart

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:sky/framework/components/popup_menu.dart';
+import 'package:sky/framework/fn.dart';
+import 'package:sky/framework/theme/typography.dart' as typography;
+import 'package:sky/framework/theme/view-configuration.dart';
+import 'stock_arrow.dart';
+import 'stock_data.dart';
+
+class StockMenu extends Component {
+  static final Style _style = new Style('''
+    position: absolute;
+    right: 8px;
+    top: ${8 + kStatusBarHeight}px;''');
+
+  StockMenu({Object key}) : super(key: key);
+
+  Node build() {
+    return new Container(
+      style: _style,
+      children: [
+        new PopupMenu(
+          items: [
+            [new Text('Add stock')],
+            [new Text('Remove stock')],
+            [new Text('Help & feeback')],
+          ],
+          level: 4)
+      ]
+    );
+  }
+}