Remove generated directories with 100s of files.

client/dom/generated/src/interface/CSSStyleDeclaration.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 CSSStyleDeclaration {
-
-  String cssText;
-
-  final int length;
-
-  final CSSRule parentRule;
-
-  CSSValue getPropertyCSSValue(String propertyName);
-
-  String getPropertyPriority(String propertyName);
-
-  String getPropertyShorthand(String propertyName);
-
-  String getPropertyValue(String propertyName);
-
-  bool isPropertyImplicit(String propertyName);
-
-  String item(int index);
-
-  String removeProperty(String propertyName);
-
-  void setProperty(String propertyName, String value, [String priority]);
-}