Isolates: allow sending of arbitrary objects in dart2js.

tests/isolate/object_leak_test.dart

Index: tests/isolate/object_leak_test.dart
diff --git a/tests/isolate/object_leak_test.dart b/tests/isolate/object_leak_test.dart
index 4511b43fd99bfe74285ccb437f40588c55e85c14..d15f2b51ca8518a3dcf6be9109e7ad3e7f2c45df 100644
--- a/tests/isolate/object_leak_test.dart
+++ b/tests/isolate/object_leak_test.dart
@@ -16,25 +16,23 @@ class A {
 }
 
 fun(msg) {
-  print("received: ${msg.x}");
-  msg.x = 1;
-  print("done updating: ${msg.x}");
+  var a = msg[0];
+  var replyTo = msg[1];
+  print("received: ${a.x}");
+  a.x = 1;
+  print("done updating: ${a.x}");
+  replyTo.send("done");
 }
 
 main() {
   asyncStart();
   var a = new A();
-  // Sending an A object to another isolate should not work.
-  Isolate.spawn(fun, a).then((isolate) {
-    new Timer(const Duration(milliseconds: 300), () {
-      // Changes in other isolate must not reach here.
-      Expect.equals(0, a.x);
-      asyncEnd();
-    });
-  }, onError: (e) {
-    // Sending an A isn't required to work.
-    // It works in the VM, but not in dart2js.
-    print("Send of A failed:\n$e");
+  ReceivePort rp = new ReceivePort();
+  Isolate.spawn(fun, [a, rp.sendPort]);
+  rp.first.then((msg) {
+    Expect.equals("done", msg);
+    // Changes in other isolate must not reach here.
+    Expect.equals(0, a.x);
     asyncEnd();
   });
 }