Revert "Adding a mechanism to 'upgrade' the Dart type of elements"

tests/html/custom/element_upgrade_test.dart

-// Copyright (c) 2014, 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 register_element_proxy_test;
-
-import 'dart:async';
-import 'dart:html';
-import 'dart:js' as js;
-import 'package:unittest/html_config.dart';
-import 'package:unittest/unittest.dart';
-import '../utils.dart';
-
-class FooElement extends HtmlElement {
-  static final tag = 'x-foo';
-
-  final int initializedField = 666;
-  js.JsObject _proxy;
-
-  factory FooElement() => new Element.tag(tag);
-  FooElement.created() : super.created() {
-    _proxy = new js.JsObject.fromBrowserObject(this);
-  }
-
-  String doSomething() => _proxy.callMethod('doSomething');
-
-  bool get fooCreated => _proxy['fooCreated'];
-}
-
-main() {
-  useHtmlConfiguration();
-
-  var registered = false;
-  var upgrader;
-  setUp(() => customElementsReady.then((_) {
-    if (!registered) {
-      registered = true;
-      upgrader = document.createElementUpgrader(FooElement);
-      js.context['upgradeListener'] = (e) {
-        upgrader.upgrade(e);
-      };
-
-      document.register('custom-element', CustomElement);
-    }
-  }));
-
-  test('created gets proxied', () {
-    var element = document.createElement(FooElement.tag);
-    expect(element is FooElement, isTrue);
-    expect(element.initializedField, 666);
-    expect(element.text, 'constructed');
-
-    js.context.callMethod('validateIsFoo', [element]);
-
-    expect(element.doSomething(), 'didSomething');
-    expect(element.fooCreated, true);
-  });
-
-  test('dart constructor works', () {
-    var element = new FooElement();
-    expect(element is FooElement, isTrue);
-    expect(element.text, 'constructed');
-
-    js.context.callMethod('validateIsFoo', [element]);
-
-    expect(element.doSomething(), 'didSomething');
-  });
-
-  test('cannot create upgrader for interfaces', () {
-    expect(() {
-      document.createElementUpgrader(HtmlElementInterface);
-    }, throws);
-  });
-
-  test('cannot upgrade interfaces', () {
-    expect(() {
-      upgrader.upgrade(new HtmlElementInterface());
-    }, throws);
-  });
-
-  test('cannot upgrade more than once', () {
-    var fooElement = new FooElement();
-    expect(() {
-      upgrader.upgrade(fooElement);
-    }, throws);
-  });
-
-  test('cannot upgrade non-matching elements', () {
-    expect(() {
-      upgrader.upgrade(new DivElement());
-    }, throws);
-  });
-
-  test('cannot upgrade custom elements', () {
-    var custom = new CustomElement();
-    expect(() {
-      upgrader.upgrade(custom);
-    }, throws);
-  });
-
-  test('can upgrade with extendsTag', () {
-    var upgrader =
-        document.createElementUpgrader(CustomDiv, extendsTag: 'div');
-    var div = new DivElement();
-    var customDiv = upgrader.upgrade(div);
-    expect(customDiv is CustomDiv, isTrue);
-
-    var htmlElement = document.createElement('not-registered');
-    expect(() {
-      upgrader.upgrade(htmlElement);
-    }, throws);
-  });
-
-  test('cannot create upgrader for built-in types', () {
-    expect(() {
-      document.createElementUpgrader(HtmlElement);
-    }, throws);
-  });
-}
-
-class HtmlElementInterface implements HtmlElement {
-  HtmlElementInterface.created();
-}
-
-class CustomDiv extends DivElement {
-  CustomDiv.created() : super.created();
-}
-
-class CustomElement extends HtmlElement {
-  factory CustomElement() => document.createElement('custom-element');
-  CustomElement.created() : super.created();
-}