void PaintLayerScrollableArea::UpdateScrollbarProportions() {
  if (Scrollbar* horizontal_scrollbar = HorizontalScrollbar())
    horizontal_scrollbar->SetProportion(VisibleWidth(), ContentsSize().Width());
  if (Scrollbar* vertical_scrollbar = VerticalScrollbar())
    vertical_scrollbar->SetProportion(VisibleHeight(), ContentsSize().Height());
}

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.