Revert "dart2js: add support for configuration-specific imports."

pkg/compiler/lib/src/parser/class_element_parser.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.
 
 library dart2js.parser.classes;
 
 import '../tokens/token.dart' show
     Token;
 
 import 'listener.dart' show
     Listener;
 import 'partial_parser.dart' show
     PartialParser;
 
 class ClassElementParser extends PartialParser {
-  ClassElementParser(Listener listener)
-      : super(listener, enableConditionalDirectives: false);
+  ClassElementParser(Listener listener) : super(listener);
 
   Token parseClassBody(Token token) => fullParseClassBody(token);
 }