ScrollbarStyles(PRUint8 h, PRUint8 v) : mHorizontal(h), mVertical(v) {}
ScrollbarStyles(PRInt32 h, PRInt32 v) : mHorizontal(h), mVertical(v) {}
    ScrollbarStyles(PRUint8 h, PRUint8 v) : mHorizontal(h), mVertical(v) {}