Allow named parameters in const constructor invocations.

compiler/java/com/google/dart/compiler/ast/DartNamedExpression.java

Index: compiler/java/com/google/dart/compiler/ast/DartNamedExpression.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartNamedExpression.java b/compiler/java/com/google/dart/compiler/ast/DartNamedExpression.java
index a49c1cc9d7098fa301229b616a42cc0d923ad0fd..8616f6c320071c129d7af3b7aa19497b4b2f08ab 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartNamedExpression.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartNamedExpression.java
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
@@ -46,7 +46,6 @@ public class DartNamedExpression extends DartExpression {
     if (expression != null) {
       expression.accept(visitor);
     }
-    expression.accept(visitor);
   }
 
   @Override