Implement spawnDomUri.

tests/html/dom_isolates_test.dart.child_isolate.dart

Index: tests/html/dom_isolates_test.dart.child_isolate.dart
diff --git a/tests/html/dom_isolates_test.dart.child_isolate.dart b/tests/html/dom_isolates_test.dart.child_isolate.dart
new file mode 100644
index 0000000000000000000000000000000000000000..31e97d2bc8a9efb817f5fd6f09c1f7f09f7900fb
--- /dev/null
+++ b/tests/html/dom_isolates_test.dart.child_isolate.dart
@@ -0,0 +1,16 @@
+// 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
+
+import 'dart:html';
+import 'dart:isolate';
+
+main() {
+  port.receive((msg, replyTo) {
+    if (msg != 'check') {
+      replyTo.send('wrong msg: $msg');
+    }
+    replyTo.send('${window.location}');
+    port.close();
+  });
+}