request-animation-frame-timestamps-advance.html

<!DOCTYPE html>
<title>Tests the timestamps provided to requestAnimationFrame callbacks advance</title>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>

<script>
  async_test(t => {
    function busyWait(millis) {
      var start = Date.now();
      while (Date.now() - start < millis) { }
    }

    var firstTimestamp;
    var secondTimestamp;

    window.requestAnimationFrame(function(timestamp) {
      firstTimestamp = timestamp;
      t.step(function() {
        assert_true(!!firstTimestamp);
      });
      window.requestAnimationFrame(function(timestamp) {
        secondTimestamp = timestamp;
        t.step(function() {
          assert_true(!!secondTimestamp);
          assert_true(secondTimestamp > firstTimestamp);
        });
        t.done();
      });
      busyWait(10);
    });
  }, "Test the timestamps provided to rAF callbacks advance");
</script>

chromium/third_party/blink/web_tests/fast/animation/request-animation-frame-timestamps-advance.html