third_party/WebKit/LayoutTests/compositing/overflow/mixed-composited-nested-sticky.html

<style>
body {
  margin: 0;
}

.container {
  width: 200px;
  height: 2000px;
}

.composited {
  /* Forces promotion without creating a stacking context. */
  backface-visibility: hidden;
}

.outerSticky {
  position: sticky;
  top: 50px;
  background-color: green;
  width: 200px;
  height: 200px;
}

.middleSticky {
  position: sticky;
  top: 100px;
  background-color: yellow;
  width: 200px;
  height: 100px;
}

.innerSticky {
  position: sticky;
  top: 125px;
  background-color: red;
  width: 200px;
  height: 50px;
}
</style>

<script>
if (window.testRunner)
  testRunner.waitUntilDone();

function finishTest() {
  window.scrollTo(0, 200);
  if (window.testRunner)
    testRunner.notifyDone();
}

window.addEventListener('load', function() {
  requestAnimationFrame(function() {
    requestAnimationFrame(finishTest);
  });
});
</script>

<div class="container">
  <div class="outerSticky">
    <div class="middleSticky composited">
      <div class="innerSticky composited"></div>
    </div>
  </div>
</div>