LayoutTests/media/modern-media-controls/scheduler/single-callback-when-registered-multiple-times.html

<script src="../../../resources/js-test-pre.js"></script>
<script src="../../../../Source/WebCore/Modules/modern-media-controls/controls/scheduler.js" type="text/javascript"></script>
<script src="../resources/media-controls-utils.js" type="text/javascript"></script>
<script type="text/javascript">

description("This test checks that calling `scheduleLayout()` multiple times with the same function yields a single call to that function.");

window.jsTestIsAsync = true;

if (window.testRunner)
    window.testRunner.dumpAsText();

let numberOfCalls = 0;
function layout()
{
    numberOfCalls++;
}

scheduler.frameDidFire = function()
{
    shouldBe("numberOfCalls", "1");
    finishMediaControlsTest();
};

scheduler.scheduleLayout(layout);
scheduler.scheduleLayout(layout);
scheduler.scheduleLayout(layout);

</script>
<script src="../../../resources/js-test-post.js"></script>