Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_CompositionEventWrappingImplementation.dart

-// Copyright (c) 2011, 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.
-
-class _CompositionEventWrappingImplementation extends _UIEventWrappingImplementation implements CompositionEvent {
-  _CompositionEventWrappingImplementation() : super() {}
-
-  static create__CompositionEventWrappingImplementation() native {
-    return new _CompositionEventWrappingImplementation();
-  }
-
-  String get data() { return _get_data(this); }
-  static String _get_data(var _this) native;
-
-  void initCompositionEvent(String typeArg, bool canBubbleArg, bool cancelableArg, DOMWindow viewArg, String dataArg) {
-    _initCompositionEvent(this, typeArg, canBubbleArg, cancelableArg, viewArg, dataArg);
-    return;
-  }
-  static void _initCompositionEvent(receiver, typeArg, canBubbleArg, cancelableArg, viewArg, dataArg) native;
-
-  String get typeName() { return "CompositionEvent"; }
-}