<!DOCTYPE html>
<body>
<style>
    
    body {
        margin: 0;
    }
    
    div {
        height: 100px;
    }

    #target {
        left: 0;
        width: 100px;
        background-color: red;
    }

    #cache {
        top: 0;
        left: 25px;
        width: 775px;
        position: absolute;
        background-color: black;
    }

</style>
<div id="target"></div>
<div id="cache"></div>
<script>

if (window.testRunner)
    testRunner.waitUntilDone();

document.getElementById("target").animate({ transform: "translateX(700px)" }, { delay: 10, duration: 1000 })
requestAnimationFrame(() => {
    setTimeout(() => {
        if (window.testRunner)
            testRunner.notifyDone();
    }, 100);
});

</script>
</body>