anchor.diff:        painter(childContext, offset);
         childContext._stopRecordingIfNeeded();
       } else {
  -      canvas.saveLayer(bounds.shift(offset), _disableAntialias);
  +      canvas.saveLayer(bounds.shift(offset), _defaultPaint);
         canvas.clipPath(clipPath.shift(offset));
         painter(this, offset);
         canvas.restore();
  
positive.code:     _canvas = null;
    }
  
    static final Paint _disableAntialias = new Paint()..isAntiAlias = false;
  
    /// Hints that the painting in the current layer is complex and would benefit
    /// from caching.
  
negative.code:       painter(childContext, offset);
        childContext._stopRecordingIfNeeded();
      } else {
        canvas.saveLayer(offsetBounds, _defaultPaint);
        canvas.clipRRect(offsetClipRRect);
        painter(this, offset);
        canvas.restore();
  