Remove generated directories with 100s of files.

client/html/generated/html/dartium/_WorkerFactoryProvider.dart

Index: client/html/generated/html/dartium/_WorkerFactoryProvider.dart
diff --git a/client/html/generated/html/dartium/_WorkerFactoryProvider.dart b/client/html/generated/html/dartium/_WorkerFactoryProvider.dart
deleted file mode 100644
index 4afe4651178dc1adeb6e9b90bab64863316f9e1b..0000000000000000000000000000000000000000
--- a/client/html/generated/html/dartium/_WorkerFactoryProvider.dart
+++ /dev/null
@@ -1,8 +0,0 @@
-// 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.
-
-class _WorkerFactoryProvider {
-  factory Worker(String scriptUrl) =>
-      _wrap(new dom.Worker(_unwrap(scriptUrl)));
-}