HTTP loading tests and package root support

tests/standalone/http_launch_data/http_spawn_main.dart

Index: tests/standalone/http_launch_data/http_spawn_main.dart
diff --git a/tests/standalone/http_launch_data/http_spawn_main.dart b/tests/standalone/http_launch_data/http_spawn_main.dart
new file mode 100644
index 0000000000000000000000000000000000000000..dadc38558c8fb56cddaa76867e2bc3933e89223d
--- /dev/null
+++ b/tests/standalone/http_launch_data/http_spawn_main.dart
@@ -0,0 +1,18 @@
+// 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.
+
+library http_lanuch_main;
+
+import 'dart:isolate';
+import 'dart:io';
+
+main() {
+  int port = int.parse(new Options().arguments[0]);
+  SendPort spawnedPort =
+      spawnUri('http://127.0.0.1:$port/http_isolate_main.dart');
+  spawnedPort.call('hello').then((response) {
+    print(response);
+  });
+}
+