Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_DataTransferItemListWrappingImplementation.dart

-// Copyright (c) 2011, 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.
-
-class _DataTransferItemListWrappingImplementation extends DOMWrapperBase implements DataTransferItemList {
-  _DataTransferItemListWrappingImplementation() : super() {}
-
-  static create__DataTransferItemListWrappingImplementation() native {
-    return new _DataTransferItemListWrappingImplementation();
-  }
-
-  int get length() { return _get_length(this); }
-  static int _get_length(var _this) native;
-
-  void add(var data_OR_file, [String type = null]) {
-    if (data_OR_file is File) {
-      if (type === null) {
-        _add(this, data_OR_file);
-        return;
-      }
-    } else {
-      if (data_OR_file is String) {
-        _add_2(this, data_OR_file, type);
-        return;
-      }
-    }
-    throw "Incorrect number or type of arguments";
-  }
-  static void _add(receiver, data_OR_file) native;
-  static void _add_2(receiver, data_OR_file, type) native;
-
-  void clear() {
-    _clear(this);
-    return;
-  }
-  static void _clear(receiver) native;
-
-  DataTransferItem item(int index) {
-    return _item(this, index);
-  }
-  static DataTransferItem _item(receiver, index) native;
-
-  String get typeName() { return "DataTransferItemList"; }
-}