Removed polymer & mirror from Observatory

runtime/observatory/tests/observatory_ui/nav/top_menu/element_test.dart

Index: runtime/observatory/tests/observatory_ui/nav/top_menu/element_test.dart
diff --git a/runtime/observatory/tests/observatory_ui/nav/top_menu/element_test.dart b/runtime/observatory/tests/observatory_ui/nav/top_menu/element_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..31afda208c954ce5ea457cf9ca2422047a4274e6
--- /dev/null
+++ b/runtime/observatory/tests/observatory_ui/nav/top_menu/element_test.dart
@@ -0,0 +1,30 @@
+// 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/nav/top_menu.dart';
+
+main() {
+  NavTopMenuElement.tag.ensureRegistration();
+
+  test('instantiation', () {
+    final e = new NavTopMenuElement();
+    expect(e, isNotNull, reason: 'element correctly created');
+  });
+  group('elements', () {
+    test('created', () async {
+      final e = new NavTopMenuElement();
+      e.content = [document.createElement('content')];
+      document.body.append(e);
+      await e.onRendered.first;
+      expect(e.children.length, isNonZero, reason: 'has elements');
+      expect(e.querySelector('content'), isNotNull,
+                                                 reason: 'has content elements');
+      e.remove();
+      await e.onRendered.first;
+      expect(e.children.length, isZero, reason: 'is empty');
+    });
+  });
+}