void PaintLayerScrollableArea::DidScrollWithScrollbar(
    ScrollbarPart part,
    ScrollbarOrientation orientation) {
  WebFeature scrollbar_use_uma;
  switch (part) {
    case kBackButtonStartPart:
    case kForwardButtonStartPart:
    case kBackButtonEndPart:
    case kForwardButtonEndPart:
      scrollbar_use_uma =
          (orientation == kVerticalScrollbar
               ? WebFeature::kScrollbarUseVerticalScrollbarButton
               : WebFeature::kScrollbarUseHorizontalScrollbarButton);
      break;
    case kThumbPart:
      scrollbar_use_uma =
          (orientation == kVerticalScrollbar
               ? WebFeature::kScrollbarUseVerticalScrollbarThumb
               : WebFeature::kScrollbarUseHorizontalScrollbarThumb);
      break;
    case kBackTrackPart:
    case kForwardTrackPart:
      scrollbar_use_uma =
          (orientation == kVerticalScrollbar
               ? WebFeature::kScrollbarUseVerticalScrollbarTrack
               : WebFeature::kScrollbarUseHorizontalScrollbarTrack);
      break;
    default:
      return;
  }

  UseCounter::Count(GetLayoutBox()->GetDocument(), scrollbar_use_uma);
}

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.