third_party/WebKit/LayoutTests/fast/canvas/canvas-toDataURL-webp-maximum-quality.html

<!-- The letters in the right image should be crisp like the letters in the left image. -->
<canvas></canvas>
<img id="result">
<pre id="error"></pre>

<script>
if (window.testRunner) {
    window.testRunner.dumpAsTextWithPixelResults();
    window.testRunner.waitUntilDone();
}

var image = new Image();

image.onload = function() {
    var canvas = document.querySelector('canvas');
    canvas.width = this.width;
    canvas.height = this.height;
    canvas.getContext('2d').drawImage(this, 0, 0);

    var dataURL = canvas.toDataURL('image/webp', 1.0); // maximum quality

    if (!dataURL.match(/^data:image\/webp[;,]/))
        error.textContent += "FAIL: the dataURL should have 'image/webp' type.";
    else
        result.src = dataURL;

    if (window.testRunner)
        window.testRunner.notifyDone();
};

image.src = "resources/letters.png";
</script>