Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_PerformanceWrappingImplementation.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 _PerformanceWrappingImplementation extends DOMWrapperBase implements Performance {
-  _PerformanceWrappingImplementation() : super() {}
-
-  static create__PerformanceWrappingImplementation() native {
-    return new _PerformanceWrappingImplementation();
-  }
-
-  MemoryInfo get memory() { return _get_memory(this); }
-  static MemoryInfo _get_memory(var _this) native;
-
-  PerformanceNavigation get navigation() { return _get_navigation(this); }
-  static PerformanceNavigation _get_navigation(var _this) native;
-
-  PerformanceTiming get timing() { return _get_timing(this); }
-  static PerformanceTiming _get_timing(var _this) native;
-
-  String get typeName() { return "Performance"; }
-}