<!DOCTYPE html>
<style>
  .container {
    height: 500px;
    width: 300px;
    overflow: scroll;
  }

  .scrolled {
    height: 50px;
    width: 100px;
    background: orange;
    margin: 15px;
    transform: translateZ(0);
  }
</style>
<script>
  if (window.internals)
    window.internals.settings.setPreferCompositingToLCDTextEnabled(true);

  onload = function()
  {
    var selection = getSelection();

    var range = document.createRange();
    range.selectNode(document.getElementById("selection"));
    selection.addRange(range);
  }
</script>

This test passes if the highlighted area includes the gaps between scrolled children.

<div class="container">
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled" id="selection">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
  <div class="scrolled">Lorem Ipsum</div>
</div>