Remove generated directories with 100s of files.

client/html/generated/html/frog/_MediaStreamFactoryProvider.dart

Index: client/html/generated/html/frog/_MediaStreamFactoryProvider.dart
diff --git a/client/html/generated/html/frog/_MediaStreamFactoryProvider.dart b/client/html/generated/html/frog/_MediaStreamFactoryProvider.dart
deleted file mode 100644
index 53a28cb7aa1aa0afab5cbe6ac9a09e61f87bd436..0000000000000000000000000000000000000000
--- a/client/html/generated/html/frog/_MediaStreamFactoryProvider.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 _MediaStreamFactoryProvider {
-  factory MediaStream(MediaStreamTrackList audioTracks, MediaStreamTrackList videoTracks) native
-      '''return new MediaStream(audioTracks, videoTracks);''';
-}