One more factory -> default pass.

dart/tests/language/src/InterfaceFactoryTest.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.
 //
 // Test that the two major variations of interface factories work.
 
 // Variant 1.  The factory class implements the interface and provides
 // a default implementation of the interface.
 
-interface Interface1 factory DefaultImplementation {
+interface Interface1 default DefaultImplementation {
   Interface1(var secret);
   Interface1.named();
 
   GetSecret();
 }
 
 class DefaultImplementation implements Interface1 {
   int _secret;
 
   DefaultImplementation(int this._secret) {}
   DefaultImplementation.named() : this._secret = 11 {}
 
   int GetSecret() { return _secret; }
 
   static testMain() {
     Expect.equals(7, new Interface1(7).GetSecret());
     Expect.equals(11, new Interface1.named().GetSecret());
   }
 }
 
 // Variant 2.  The factory class provides factory constructors for the
 // interface.
 
-interface Interface2 factory FactoryProvider {
+interface Interface2 default FactoryProvider {
   Interface2(var secret);
   Interface2.named();
 
   GetSecret();
 }
 
 class SomeImplementation implements Interface2 {
   String _secret;
 
   SomeImplementation(String one, String two) : _secret = one + two {}
@@ skipping 14 matching lines @@
   static testMain() {
     Expect.equals("cobracobra", new Interface2("cobra").GetSecret());
     Expect.equals("NamedConstructor", new Interface2.named().GetSecret());
   }
 }
 
 main() {
   DefaultImplementation.testMain();
   FactoryProvider.testMain();
 }