- Properly setup an Api scope before calling out through the API.

tests/language/deferred_in_isolate_test.dart

+// Copyright (c) 2014, 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 deferred libraries are supported from isolates other than the root
+// isolate.
+
+import 'dart:isolate';
+
+main() {
+  try {
+    var receivePort = new RawReceivePort();
+    var expectedMsg = "Deferred Loaded.";
+
+    receivePort.handler = (msg) {
+      if (msg != expectedMsg) {
+        print("Test failed.");
+        throw msg;  // Fail the test if the message is not expected.
+      }
+      print('Test done.');
+      receivePort.close();
+    };
+
+    var stopwatch = new Stopwatch()..start();
+    Isolate.spawnUri(new Uri(path: 'deferred_in_isolate_app.dart'),
+                             [expectedMsg],
+                             [receivePort.sendPort]).then((isolate) {
+      print('Isolate spawn: ${stopwatch.elapsedMilliseconds}ms');
+    }).catchError((error) {
+      print(error);
+    });
+  } catch (exception, stackTrace) {
+    print('Test failed.');
+    print(exception);
+    print(stackTrace);
+    rethrow;
+  }
+}