Make stocksapp.dart almost pass the dart analyzer.

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 88 matching lines @@
     _flingAnimationId = null;
   }
 
   void _updateFling(double timeStamp) {
     double scrollDelta = _flingCurve.update(timeStamp);
     if (!_scrollBy(scrollDelta))
       return _stopFling();
     _scheduleFlingUpdate();
   }
 
-  void _handleScrollUpdate(sky.Event event) {
+  void _handleScrollUpdate(sky.GestureEvent event) {
     _scrollBy(-event.dy);
   }
 
-  void _handleFlingStart(sky.Event event) {
+  void _handleFlingStart(sky.GestureEvent event) {
     setState(() {
       _flingCurve = new FlingCurve(-event.velocityY, event.timeStamp);
       _scheduleFlingUpdate();
     });
   }
 
-  void _handleFlingCancel(sky.Event event) {
+  void _handleFlingCancel(sky.GestureEvent event) {
     _stopFling();
   }
 
-  void _handleWheel(sky.Event event) {
+  void _handleWheel(sky.WheelEvent event) {
     _scrollBy(-event.offsetY);
   }
 }