anchor.diff:      }
     }
   
  +  /// The device pixel ratio to provide the child.
     double get scale => _scale;
     double _scale;
     void set scale (double value) {
  
positive.code:       ..devicePixelRatio = scale;
      return (await _view.layoutChild(_viewKey, layoutParams)).info;
    }
  
    String toString() {
      return '$runtimeType(url: $url)';
    }
  }
  
  class RenderChildView extends RenderBox {
    RenderChildView({
      ChildViewConnection child,
      double scale
    }) : _child = child, _scale = scale;
  
    ChildViewConnection get child => _child;
    ChildViewConnection _child;
    void set child (ChildViewConnection value) {
  
negative.code: mojom.ViewProxy _initViewProxy() {
    int viewHandle = ui.takeViewHandle();
    assert(() {
      if (viewHandle == core.MojoHandle.INVALID)
        debugPrint('Child view are supported only when running in Mojo shell.');
      return true;
    });
  