chromium/third_party/blink/web_tests/paint/markers/marker-invalidation-multiline-expected.html

<!DOCTYPE html>
<style>
  div {
    width: 100px;
    height: 100px;
    font-size: 15px;
  }
</style>

<div id="markAllSpelling">aaaaaa aaaaaa aaaaaa</div>
<div id="markNoSpelling">bbbbbb bbbbbb bbbbbb</div>

<script>
function addSpellingMarker(elem, start, end) {
    const range = document.createRange();
    const textNode = elem.firstChild;
    range.setStart(textNode, start);
    range.setEnd(textNode, end);
    if (typeof internals !== 'undefined')
        internals.setMarker(document, range, 'spelling');
};

onload = function() {
    addSpellingMarker(markAllSpelling, 0, 6);
    addSpellingMarker(markAllSpelling, 14, 20);
  };
</script>