Add dummy dart:html library for documentation.

lib/html/doc/interface/OperationNotAllowedException.dart

+// 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: Do not edit - generated code.
+
+/// @domName OperationNotAllowedException
+interface OperationNotAllowedException {
+
+  static final int NOT_ALLOWED_ERR = 1;
+
+  /** @domName OperationNotAllowedException.code */
+  final int code;
+
+  /** @domName OperationNotAllowedException.message */
+  final String message;
+
+  /** @domName OperationNotAllowedException.name */
+  final String name;
+
+  /** @domName OperationNotAllowedException.toString */
+  String toString();
+}