Updates the corelib to the new default specification for interfaces and new factory syntax

corelib/src/promise.dart

Index: corelib/src/promise.dart
diff --git a/corelib/src/promise.dart b/corelib/src/promise.dart
index 711c6f398dae43f5aea92a4ba56090d1d1cdb7b2..d3d2f7c76c3fb82fb305caa1c331b4b5f0697462 100644
--- a/corelib/src/promise.dart
+++ b/corelib/src/promise.dart
@@ -5,7 +5,7 @@
 // Dart core library.
 
 /** A promise to value of type [T] that may be computed asynchronously. */
-interface Promise<T> factory PromiseImpl<T> {
+interface Promise<T> default PromiseImpl<T> {
 
   Promise();
 
@@ -90,7 +90,7 @@ interface Promise<T> factory PromiseImpl<T> {
 }
 
 
-interface Proxy extends Promise<bool> factory ProxyImpl {
+interface Proxy extends Promise<bool> default ProxyImpl {
 
   Proxy.forPort(SendPort port);
   Proxy.forIsolate(Isolate isolate);