Execute callbacks from JS in the correct zone

tests/html/js_test.dart

Index: tests/html/js_test.dart
diff --git a/tests/html/js_test.dart b/tests/html/js_test.dart
index 081ab0270576c4bd3a86d22885eae90a21c73fba..7bdee2d50c520bb1f676125f6b07b8817bbf4b56 100644
--- a/tests/html/js_test.dart
+++ b/tests/html/js_test.dart
@@ -228,6 +228,8 @@ class Callable {
   call() => 'called';
 }
 
+typedef ThreeArgFunction(a, b, c);
+
 main() {
   _injectJs();
   useHtmlConfiguration();
@@ -659,6 +661,20 @@ main() {
       context.deleteProperty('callback');
     });
 
+    test('invoke Dart callback from JS in a Zone', () {
+      expect(() => context.callMethod('invokeCallback'), throws);
+
+      var childZone = Zone.current.fork();
+      childZone.run(() {
+        context['callback'] = () {
+          expect(Zone.current, childZone);
+        };
+      });
+      context.callMethod('invokeCallback');
+
+      context.deleteProperty('callback');
+    });
+
     test('callback as parameter', () {
       expect(context.callMethod('getTypeOf', [context['razzle']]),
           equals("function"));
@@ -694,6 +710,13 @@ main() {
       context.deleteProperty('callable');
     });
 
+    test('Dart closures should survive a round-trip to JS', () {
+      context['callback'] = (a, b, c) => a + b + c;
+      var f = context['callback'];
+      expect(f, new isInstanceOf<ThreeArgFunction>());
+      context.deleteProperty('callback');
+    });
+
   });
 
   group('JsObject.jsify()', () {