Add all dart:html tests from the sdk to test/codegen.

test/codegen/lib/html/dart_object_local_storage_test.dart

+library DartObjectLocalStorageTest;
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'dart:html';
+
+// TODO(vsm): Rename this to wrapper_caching_test or similar.  It's
+// basically a port of dom/dart_object_local_storage_test.dart.  For
+// wrapping implementation of dart:html (i.e., the dartium one), it is
+// effectively testing dart_object_local_storage in the underlying dom
+// object.
+main() {
+  useHtmlConfiguration();
+
+  BodyElement body = document.body;
+  Storage localStorage = window.localStorage;
+  Storage sessionStorage = window.sessionStorage;
+  var element = new Element.tag('canvas');
+  element.id = 'test';
+  body.append(element);
+
+  test('body', () {
+      expect(body, equals(document.body));
+  });
+  test('localStorage', () {
+      expect(localStorage, equals(window.localStorage));
+  });
+  test('sessionStorage', () {
+      expect(sessionStorage, equals(window.sessionStorage));
+  });
+  test('unknown', () {
+      var test = document.query('#test');
+      expect(element, equals(test));
+  });
+}