Refactor Future constructors.

tests/lib/async/future_delayed_error_test.dart

Index: tests/lib/async/future_delayed_error_test.dart
diff --git a/tests/lib/async/future_delayed_error_test.dart b/tests/lib/async/future_delayed_error_test.dart
index 15553723f576417f205140e4c65239d7ab27f431..be16cf03b6597eaefb2f7c0216a9e68d1c956110 100644
--- a/tests/lib/async/future_delayed_error_test.dart
+++ b/tests/lib/async/future_delayed_error_test.dart
@@ -12,7 +12,7 @@ testImmediateError() {
   // An open ReceivePort keeps the VM running. If the error-handler below is not
   // executed then the test will fail with a timeout.
   var port = new ReceivePort();
-  var future = new Future.immediateError("error");
+  var future = new Future.error("error");
   future.catchError((error) {
     port.close();
     Expect.equals(error, "error");