Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_FileWriterSyncWrappingImplementation.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 _FileWriterSyncWrappingImplementation extends DOMWrapperBase implements FileWriterSync {
-  _FileWriterSyncWrappingImplementation() : super() {}
-
-  static create__FileWriterSyncWrappingImplementation() native {
-    return new _FileWriterSyncWrappingImplementation();
-  }
-
-  int get length() { return _get_length(this); }
-  static int _get_length(var _this) native;
-
-  int get position() { return _get_position(this); }
-  static int _get_position(var _this) native;
-
-  void seek(int position) {
-    _seek(this, position);
-    return;
-  }
-  static void _seek(receiver, position) native;
-
-  void truncate(int size) {
-    _truncate(this, size);
-    return;
-  }
-  static void _truncate(receiver, size) native;
-
-  void write(Blob data) {
-    _write(this, data);
-    return;
-  }
-  static void _write(receiver, data) native;
-
-  String get typeName() { return "FileWriterSync"; }
-}