LayoutTests/webgl/webgl-worker.html

<!DOCTYPE html><!-- webkit-test-runner [ UseGPUProcessForWebGLEnabled=true OffscreenCanvasEnabled=true ] -->
<html>
<body>
<script>
function runTest() {
    if (!window.Worker) {
        document.body.innerHTML +=  "<p>Workers not supported";
        return;
    }

    if (window.testRunner) {
        testRunner.waitUntilDone();
        testRunner.dumpAsText();
    }

    const worker = new Worker("./resources/webgl-worker.js");
    worker.addEventListener("message", (e) => {
        for (result of e.data)
            document.body.innerHTML += `<p>${result}` ;
        if (window.testRunner)
            testRunner.notifyDone();
    });
}
runTest();
 </script>
</body>
</html>