bool RenderTheme::isSpinUpButtonPartHovered(const RenderObject* o) const
{
    Node* node = o->node();
    if (!node || !node->active() || !node->isElementNode()
        || !static_cast<Element*>(node)->isSpinButtonElement())
        return false;
    SpinButtonElement* element = static_cast<SpinButtonElement*>(node);
    return element->onUpButton();
}