Fix regression in meta-serializing rules

pkg/serialization/test/serialization_test.dart

Index: pkg/serialization/test/serialization_test.dart
diff --git a/pkg/serialization/test/serialization_test.dart b/pkg/serialization/test/serialization_test.dart
index db5b5f1c07e7b952c93a4bae6c0ebd98cb9b82af..c65721a7be307177fc6ea4d4ec1ddc63816366aa 100644
--- a/pkg/serialization/test/serialization_test.dart
+++ b/pkg/serialization/test/serialization_test.dart
@@ -235,6 +235,25 @@ main() {
     runRoundTripTest(nodeSerializerReflective);
   });
 
+  test('round-trip with explicit self-description', () {
+    // We provide a setup function which, when run the second time,
+    // returns a blank serialization, to make sure it will fail
+    // the second time.
+    var s;
+    oneShotSetup(node) {
+      if (s == null) {
+        s = nodeSerializerReflective(node)..selfDescribing = true;
+        return s;
+      } else {
+        s = null;
+        return new Serialization.blank()
+            ..namedObjects['Node'] = reflect(new Node('')).type;;
+      }
+    }
+
+    runRoundTripTest(oneShotSetup);
+  });
+
   test('round-trip ClosureRule', () {
     runRoundTripTest(nodeSerializerNonReflective);
   });