Serialize exports scopes.

pkg/front_end/testcases/export_test.dart

Index: pkg/front_end/testcases/export_test.dart
diff --git a/pkg/front_end/testcases/export_test.dart b/pkg/front_end/testcases/export_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a95dbfa242da5b8416f1e99935d490c283981641
--- /dev/null
+++ b/pkg/front_end/testcases/export_test.dart
@@ -0,0 +1,16 @@
+// Copyright (c) 2017, 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.
+
+/// Test that exports are serialized in platform.dill.
+
+// Note: "dart:profiler" exports UserTag from "dart:developer". This is
+// somewhat brittle and we should extend this test framework to be able to deal
+// with multiple .dill files.
+import 'dart:profiler' show UserTag;
+
+export 'dart:core' show print;
+
+main() {
+  print(UserTag);
+}