Remove generated directories with 100s of files.

client/dom/generated/src/interface/HTMLVideoElement.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 HTMLVideoElement extends HTMLMediaElement {
-
-  int height;
-
-  String poster;
-
-  final int videoHeight;
-
-  final int videoWidth;
-
-  final int webkitDecodedFrameCount;
-
-  final bool webkitDisplayingFullscreen;
-
-  final int webkitDroppedFrameCount;
-
-  final bool webkitSupportsFullscreen;
-
-  int width;
-
-  void webkitEnterFullScreen();
-
-  void webkitEnterFullscreen();
-
-  void webkitExitFullScreen();
-
-  void webkitExitFullscreen();
-}