Make it possible to run a test in sky_shell

sky/tests/resources/unit.dart

+
+import "dart:sky.internals" as internals;
+
+import 'package:sky/mojo/shell.dart' as shell;
+import 'package:mojom/sky/test_harness.mojom.dart';
+
 import "third_party/unittest/unittest.dart";
-import "dart:sky.internals" as internals;
+
+void notifyTestComplete(String result) {
+  TestHarnessProxy test_harness = new TestHarnessProxy.unbound();
+  shell.requestService("mojo:sky_viewer", test_harness);
+  test_harness.ptr.onTestComplete(result, null);
+  test_harness.close();
+
+  internals.notifyTestComplete("DONE");
+}
 
 class _SkyConfig extends SimpleConfiguration {
   void onDone(bool success) {
     try {
       super.onDone(success);
     } catch (ex) {
       print(ex.toString());
     }
 
-    internals.notifyTestComplete("DONE");
+    notifyTestComplete("DONE");
   }
 }
 
 final _singleton = new _SkyConfig();
 
 void initUnit() {
   unittestConfiguration = _singleton;
 }