void RenderScrollbarPart::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderBlock::styleDidChange(diff, oldStyle);
    setInline(false);
    clearPositionedState();
    setFloating(false);
    setHasOverflowClip(false);
    if (oldStyle && m_scrollbar && m_part != NoPart && diff >= StyleDifferenceRepaint)
        m_scrollbar->theme()->invalidatePart(*m_scrollbar, m_part);
}
void LayoutScrollbarPart::styleDidChange(StyleDifference diff, const ComputedStyle* oldStyle)
{
    LayoutBlock::styleDidChange(diff, oldStyle);
    setInline(false);
    clearPositionedState();
    setFloating(false);
    setHasOverflowClip(false);
    if (oldStyle && m_scrollbar && m_part != NoPart && (diff.needsPaintInvalidation() || diff.needsLayout()))
        m_scrollbar->theme()->invalidatePart(m_scrollbar, m_part);
}