chromium/src/third_party/blink/renderer/core/testing/data/composited_selection_bounds_split_layer.html

<style>
    @font-face {
        font-family: ahem;
        src: url(Ahem.ttf);
    }

    * {
        font-family: ahem;
    }

    .composited {
        will-change: transform;
    }
</style>
<div id="layer1" class="composited">The quick brown fox</div>
<div id="layer2" class="composited">jumped over the lazy dog.</div>
<script>
    var range = document.createRange();
    var layer1 = document.getElementById("layer1");
    var textNode1 = layer1.firstChild;
    range.setStart(textNode1, 5);
    var layer2 = document.getElementById("layer2");
    var textNode2 = layer2.firstChild;
    range.setEnd(textNode2, 10);
    document.getSelection().addRange(range);

    window.expectedResult = [layer1, 60, 0, 60, 12, layer2, 120, 0, 120, 12];
</script>