LayoutTests/fast/canvas/commit.html

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

window.addEventListener("load", function () {
    var output = document.querySelector("p");
    var canvas = document.querySelector("canvas");
    var context = canvas.getContext("2d");

    if ("commit" in context)
        output.textContent = "PASS";
    else
        output.textContent = "FAIL";
}, false);

</script>
<p></p>
<canvas></canvas>