Remove generated directories with 100s of files.

client/dom/generated/src/interface/IDBRequest.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 IDBRequest {
-
-  static final int DONE = 2;
-
-  static final int LOADING = 1;
-
-  final int errorCode;
-
-  EventListener onerror;
-
-  EventListener onsuccess;
-
-  final int readyState;
-
-  final IDBAny result;
-
-  final IDBAny source;
-
-  final IDBTransaction transaction;
-
-  final String webkitErrorMessage;
-
-  void addEventListener(String type, EventListener listener, [bool useCapture]);
-
-  bool dispatchEvent(Event evt);
-
-  void removeEventListener(String type, EventListener listener, [bool useCapture]);
-}