Don't hardcode the list of events types in fn

sky/examples/fn/widgets/fixedheightscrollable.dart

 part of widgets;
 
 abstract class FixedHeightScrollable extends Component {
 
   static Style _style = new Style('''
     overflow: hidden;
     position: relative;
     will-change: transform;'''
   );
 
@@ skipping 32 matching lines @@
     double drawStart = _scrollOffset + alignmentDelta;
     int itemNumber = (drawStart / itemHeight).floor();
 
     var transformStyle =
         'transform: translateY(${(alignmentDelta).toStringAsFixed(2)}px)';
 
     var items = renderItems(itemNumber, drawCount);
 
     return new Container(
       style: _style,
-      onFlingStart: _handleFlingStart,
-      onFlingCancel: _handleFlingCancel,
-      onScrollUpdate: _handleScrollUpdate,
-      onWheel: _handleWheel,
       children: [
         new Container(
           style: _scrollAreaStyle,
           inlineStyle: transformStyle,
           children: items
         )
       ]
-    );
+    )
+    ..events.listen('gestureflingstart', _handleFlingStart)
+    ..events.listen('gestureflingcancel', _handleFlingCancel)
+    ..events.listen('gesturescrollupdate', _handleScrollUpdate)
+    ..events.listen('wheel', _handleWheel);
   }
 
   void willUnmount() {
     _stopFling();
   }
 
   bool _scrollBy(double scrollDelta) {
     var newScrollOffset = _scrollOffset + scrollDelta;
     if (minOffset != null && newScrollOffset < minOffset) {
       newScrollOffset = minOffset;
@@ skipping 43 matching lines @@
   }
 
   void _handleFlingCancel(sky.Event event) {
     _stopFling();
   }
 
   void _handleWheel(sky.Event event) {
     _scrollBy(-event.offsetY);
   }
 }