Process handled exports correctly.

tests/language/reexport_core_test.dart

+// Copyright (c) 2013, 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.
+
+// Tests that exports are handled for libraries loaded prior to the entry point
+// library.
+//
+// This test uses the fact that dart2js loads dart:core before the
+// reexport_core_helper and reexport_core_test libraries and the exports of
+// dart:core is therefore computed before the exports of reexport_core_helper.
+
+library reexport_core_test;
+
+import 'reexport_core_helper.dart' as core;
+
+void main() {
+  var o = new Object();
+  Expect.isTrue(o is core.Object);
+}
+