Remove generated directories with 100s of files.

client/dom/generated/src/interface/HTMLSelectElement.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.
-
-interface HTMLSelectElement extends HTMLElement {
-
-  bool autofocus;
-
-  bool disabled;
-
-  final HTMLFormElement form;
-
-  final NodeList labels;
-
-  int length;
-
-  bool multiple;
-
-  String name;
-
-  final HTMLOptionsCollection options;
-
-  bool required;
-
-  int selectedIndex;
-
-  int size;
-
-  final String type;
-
-  final String validationMessage;
-
-  final ValidityState validity;
-
-  String value;
-
-  final bool willValidate;
-
-  void add(HTMLElement element, HTMLElement before);
-
-  bool checkValidity();
-
-  Node item(int index);
-
-  Node namedItem(String name);
-
-  void remove(var index_OR_option);
-
-  void setCustomValidity(String error);
-}