anchor.diff:            ),
             // sheet
             new _BottomSheet(
  -            performance: performance,
  +            performance: _performance,
               child: child
             )
           ])
  
positive.code: import 'material.dart';
  
  const Duration _kBottomSheetDuration = const Duration(milliseconds: 200);
  
  class _BottomSheet extends StatefulComponent {
    _BottomSheet({
  
negative.code:   }
  }
  
  class _ModalBottomSheetRoute extends Route {
    _ModalBottomSheetRoute({ this.completer, this.child }) {
      _performance = new Performance(duration: transitionDuration, debugLabel: 'ModalBottomSheet');
    }
  
    final Completer completer;
    final Widget child;
  
    PerformanceView get performance => _performance?.view;
    Performance _performance;
  
    bool get ephemeral => true;
    bool get modal => true;
  