<!DOCTYPE html>
<html class="test-wait">
<meta charset="utf-8">
<link rel="help" href="crbug.com/421471058">
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-actions.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<style>
  body {
    margin: 0;
  }

  #scroller {
    width: 600px;
    height: 300px;
    overflow: auto;
    scroll-marker-group: before;
    white-space: nowrap;
  }

  #scroller div {
    background: blue;
    display: inline-block;
   