anchor.diff:      this.divisions,
       this.label,
       this.activeColor,
  +    this.textTheme,
       this.onChanged,
       this.vsync,
     }) : super(key: key);
  
positive.code:       // https://github.com/flutter/flutter/issues/5938
        _labelPainter
          ..text = new TextSpan(
            style: Typography.white.body1.copyWith(fontSize: 10.0),
            text: newLabel
          )
          ..layout();
  
negative.code:     divisions: divisions,
      label: label,
      activeColor: activeColor,
      textTheme: textTheme,
      onChanged: onChanged,
      vsync: vsync,
    );
  