Record default clause for interfaces in parser.

tests/compiler/dart2js/unparser_test.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.
 
 #import('dart:uri');
 #import('parser_helper.dart');
 #import("../../../lib/compiler/compiler.dart");
 #import("../../../lib/compiler/implementation/tree/tree.dart");
 
 testUnparse(String statement) {
@@ skipping 149 matching lines @@
   testDart2Dart('main(){var a=new A(); a.foo; a.foo=5;}class A{set foo(a){}get foo(){return 5;}}');
   // Typed get/set.
   testDart2Dart('String get foo(){return "a";}main(){foo;}');
 }
 
 testFactoryConstructor() {
   testDart2Dart('main(){new A.fromFoo();}class A{A.fromFoo();}');
   // Now more complicated, with normal constructor and factory parameters.
   testDart2Dart('main(){new A.fromFoo(5);}'
       'class A{A(this.f);A.fromFoo(foo):this("f");final String f;}');
+  // Now even more complicated, with interface and default factory.
+  testDart2Dart('main(){new A.fromFoo(5); new I.fromFoo();}'
+      'class IFactory{factory I.fromFoo()=> new A(5);}'
+      'interface I default IFactory{I.fromFoo();}'
+      'class A implements I{A(this.f);A.fromFoo(foo):this("f");final String f;}');
 }
 
 main() {
   testGenericTypes();
   testForLoop();
   testEmptyList();
   testClosure();
   testIndexedOperatorDecl();
   testNativeMethods();
   testPrefixIncrements();
   testConstModifier();
   testSimpleFileUnparse();
   testSimpleObjectInstantiation();
   testSimpleTopLevelClass();
   testClassWithSynthesizedConstructor();
   testClassWithMethod();
   testVariableDefinitions();
   testGetSet();
   testFactoryConstructor();
   testTopLevelField();
 }