anchor.diff:      }
     }
   
  +  static Paint _getPaintForAlpha(int alpha) {
  +    return new Paint()
  +      ..color = new Color.fromARGB(alpha, 0, 0, 0)
  +      ..setTransferMode(sky.TransferMode.srcOver)
  +      ..isAntiAlias = false;
  +  }
  +
     void paintChildWithOpacity(RenderObject child,
                                Point childPosition,
                                Rect bounds,
  
positive.code:       _containerLayer.add(paintLayer);
        compositeChild(child, parentLayer: paintLayer);
      }
    }
  
    void paintChildWithColorFilter(RenderObject child,
  
negative.code:     assert(debugCanPaintChild(child));
      final Offset childOffset = childPosition.toOffset();
      if (!child.needsCompositing) {
        canvas.saveLayer(bounds, _getPaintForAlpha(alpha));
        canvas.translate(childOffset.dx, childOffset.dy);
        insertChild(child, Offset.zero);
        canvas.restore();
  