Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_ImageDataWrappingImplementation.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 _ImageDataWrappingImplementation extends DOMWrapperBase implements ImageData {
-  _ImageDataWrappingImplementation() : super() {}
-
-  static create__ImageDataWrappingImplementation() native {
-    return new _ImageDataWrappingImplementation();
-  }
-
-  CanvasPixelArray get data() { return _get_data(this); }
-  static CanvasPixelArray _get_data(var _this) native;
-
-  int get height() { return _get_height(this); }
-  static int _get_height(var _this) native;
-
-  int get width() { return _get_width(this); }
-  static int _get_width(var _this) native;
-
-  String get typeName() { return "ImageData"; }
-}