Add dummy dart:html library for documentation.

lib/html/doc/interface/ObjectElement.dartdoc

+// Copyright (c) 2012, 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.
+
+// WARNING:
+//   This file contains documentation that is merged into the real source.
+//   Do not make code changes here.
+
+/// @domName HTMLObjectElement
+interface ObjectElement extends Element default _Elements {
+
+  ObjectElement();
+
+  /** @domName HTMLObjectElement.align */
+  String align;
+
+  /** @domName HTMLObjectElement.archive */
+  String archive;
+
+  /** @domName HTMLObjectElement.border */
+  String border;
+
+  /** @domName HTMLObjectElement.code */
+  String code;
+
+  /** @domName HTMLObjectElement.codeBase */
+  String codeBase;
+
+  /** @domName HTMLObjectElement.codeType */
+  String codeType;
+
+  /** @domName HTMLObjectElement.contentDocument */
+  final Document contentDocument;
+
+  /** @domName HTMLObjectElement.data */
+  String data;
+
+  /** @domName HTMLObjectElement.declare */
+  bool declare;
+
+  /** @domName HTMLObjectElement.form */
+  final FormElement form;
+
+  /** @domName HTMLObjectElement.height */
+  String height;
+
+  /** @domName HTMLObjectElement.hspace */
+  int hspace;
+
+  /** @domName HTMLObjectElement.name */
+  String name;
+
+  /** @domName HTMLObjectElement.standby */
+  String standby;
+
+  /** @domName HTMLObjectElement.type */
+  String type;
+
+  /** @domName HTMLObjectElement.useMap */
+  String useMap;
+
+  /** @domName HTMLObjectElement.validationMessage */
+  final String validationMessage;
+
+  /** @domName HTMLObjectElement.validity */
+  final ValidityState validity;
+
+  /** @domName HTMLObjectElement.vspace */
+  int vspace;
+
+  /** @domName HTMLObjectElement.width */
+  String width;
+
+  /** @domName HTMLObjectElement.willValidate */
+  final bool willValidate;
+
+  /** @domName HTMLObjectElement.checkValidity */
+  bool checkValidity();
+
+  /** @domName HTMLObjectElement.setCustomValidity */
+  void setCustomValidity(String error);
+}