Remove generated directories with 100s of files.

client/dom/generated/src/interface/IDBTransaction.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 IDBTransaction {
-
-  static final int READ_ONLY = 0;
-
-  static final int READ_WRITE = 1;
-
-  static final int VERSION_CHANGE = 2;
-
-  final IDBDatabase db;
-
-  final int mode;
-
-  EventListener onabort;
-
-  EventListener oncomplete;
-
-  EventListener onerror;
-
-  void abort();
-
-  void addEventListener(String type, EventListener listener, [bool useCapture]);
-
-  bool dispatchEvent(Event evt);
-
-  IDBObjectStore objectStore(String name);
-
-  void removeEventListener(String type, EventListener listener, [bool useCapture]);
-}