Fix gesture events in fn2

sky/examples/fn2/container.dart

Index: sky/examples/fn2/container.dart
diff --git a/sky/examples/fn2/container.dart b/sky/examples/fn2/container.dart
index 0be6f50cf889814ba67353f64e5268d5541e6c2e..5abda8572005943525628d545c68a98343de998d 100644
--- a/sky/examples/fn2/container.dart
+++ b/sky/examples/fn2/container.dart
@@ -38,12 +38,17 @@ class ContainerApp extends App {
                   ),
               ])),
       ]),
-      onPointerDown: _handlePointerDown);
+      onPointerDown: _handlePointerDown,
+      onGestureTap: _handleGestureTap);
   }
 
   void _handlePointerDown(sky.PointerEvent event) {
     print("_handlePointerDown");
   }
+
+  void _handleGestureTap(sky.GestureEvent event) {
+    print("_handleGestureTap");
+  }
 }
 
 void main() {