Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_ErrorEventWrappingImplementation.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 _ErrorEventWrappingImplementation extends _EventWrappingImplementation implements ErrorEvent {
-  _ErrorEventWrappingImplementation() : super() {}
-
-  static create__ErrorEventWrappingImplementation() native {
-    return new _ErrorEventWrappingImplementation();
-  }
-
-  String get filename() { return _get_filename(this); }
-  static String _get_filename(var _this) native;
-
-  int get lineno() { return _get_lineno(this); }
-  static int _get_lineno(var _this) native;
-
-  String get message() { return _get_message(this); }
-  static String _get_message(var _this) native;
-
-  String get typeName() { return "ErrorEvent"; }
-}