Wrapping leaf nodes in non polymer elements

runtime/observatory/tests/observatory_ui/view_footer_test.dart

+// Copyright (c) 2016, 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.
+import 'dart:html';
+import 'package:unittest/unittest.dart';
+import 'package:observatory/src/elements/view_footer.dart';
+
+import 'helpers/webcomponents.dart';
+
+main() async {
+  await loadWebComponents();
+  ViewFooterElement.tag.ensureRegistration();
+
+  test('instantiation', () {
+    final ViewFooterElement e = new ViewFooterElement();
+    expect(e, isNotNull, reason: 'element correctly created');
+  });
+  test('elements created after attachment', () {
+    final ViewFooterElement e = new ViewFooterElement();
+    expect(e.children.length, isZero,
+      reason: 'is empty');
+    document.body.append(e);
+    expect(e.children.length, isNonZero,
+      reason: 'has elements');
+    e.remove();
+  });
+}