Reverts the following two commits:

pkg/compiler/lib/src/serialization/modelz.dart

 // Copyright (c) 2015, 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.
 
 /// Implementation of the element model used for deserialiation.
 ///
 /// These classes are created by [ElementDeserializer] triggered by the
 /// [Deserializer].
 
 library dart2js.serialization.modelz;
@@ skipping 2134 matching lines @@
   @override
   accept(ElementVisitor visitor, arg) {
     return visitor.visitParameterElement(this, arg);
   }
 
   @override
   bool get isLocal => true;
 
   @override
   ElementKind get kind => ElementKind.PARAMETER;
-
-  @override
-  bool get isUnnamed => false;
 }
 
 class InitializingFormalElementZ extends LocalParameterElementZ
     implements InitializingFormalElement {
   FieldElement _fieldElement;
 
   InitializingFormalElementZ(ObjectDecoder decoder) : super(decoder);
 
   @override
   FieldElement get fieldElement {
@@ skipping 241 matching lines @@
   }
 
   @override
   Node get node => throw new UnsupportedError('${this}.node');
 
   @override
   bool get hasNode => false;
 
   String toString() => 'MetadataAnnotationZ(${constant.toDartText()})';
 }