minor fixes

com.unity.uiwidgets/Runtime/material/scrollbar.cs

         }
 
         public override Widget build(BuildContext context) {
-            //TODO：uncomment here when cupertino updates are merged
-            /*if (_useCupertinoScrollbar.Value) {
+            if (_useCupertinoScrollbar.Value) {
-            }*/
+            }
+            
             return new NotificationListener<ScrollNotification>(
                 onNotification: _handleScrollNotification,
                 child: new RepaintBoundary(