Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_DirectoryReaderWrappingImplementation.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 _DirectoryReaderWrappingImplementation extends DOMWrapperBase implements DirectoryReader {
-  _DirectoryReaderWrappingImplementation() : super() {}
-
-  static create__DirectoryReaderWrappingImplementation() native {
-    return new _DirectoryReaderWrappingImplementation();
-  }
-
-  void readEntries(EntriesCallback successCallback, [ErrorCallback errorCallback = null]) {
-    _readEntries(this, successCallback, errorCallback);
-    return;
-  }
-  static void _readEntries(receiver, successCallback, errorCallback) native;
-
-  String get typeName() { return "DirectoryReader"; }
-}