Updates dartc to recognize 'default' keyword on interface and updated factory method syntax

tests/language/src/Factory3Test.dart

Index: tests/language/src/Factory3Test.dart
diff --git a/tests/language/src/Factory3Test.dart b/tests/language/src/Factory3Test.dart
index 562c70b70d30abbbbf647e7e46704a53ff91dd0d..3f95fd0604260c0947a5a72e9175b41741188dcc 100644
--- a/tests/language/src/Factory3Test.dart
+++ b/tests/language/src/Factory3Test.dart
@@ -8,12 +8,12 @@ interface Link<T> extends Iterable<T> factory LinkFactory<T> {
   Link<T> prepend(T element);
 }
 
-interface EmptyLink<T> extends Link<T> factory LinkTail<T> {
+interface EmptyLink<T> extends Link<T> default LinkTail<T> {
   const EmptyLink();
 }
 
 class LinkFactory<T> {
-  factory Link(head, [Link tail]) {
+  factory Link(T head, [Link<T> tail]) {
     return new LinkEntry<T>(head, tail);
   }
 }