chromium/third_party/blink/web_tests/images/yuv-decode-eligible/webp-image-decoding.html

<html>
<body>
<script>
  function output_results_if_complete() {
      if (++images == expectedNumberImages) {
          document.getElementById('results').innerHTML =
              document.getElementsByTagName('img')[0].width + 'x' +
              document.getElementsByTagName('img')[0].height + ' ' +
              document.getElementsByTagName('img')[1].width + 'x' +
              document.getElementsByTagName('img')[1].height + ' ' +
              document.getElementsByTagName('img')[2].width + 'x' +
              document.getElementsByTagName('img')[2].height;
          if (window.testRunner) {
              setTimeout(function() { testRunner.notifyDone() }, 0);
          }
      }
  }

  function preload_decode_append_img(url, parentNodeId) {
      const img = new Image();
      img.src = url;
      img.decode().then(() => {
          document.getElementById(parentNodeId).appendChild(img);
          output_results_if_complete();
      }).catch(() => {
          var error = document.createElement('p');
          error.innerText = 'Error loading image'
          document.body.appendChild(error);
      });
  }

  var images = 0;
  var expectedNumberImages = 3;
  preload_decode_append_img('../resources/test.webp', 'test');
  preload_decode_append_img('../resources/test2.webp', 'test2');
  preload_decode_append_img('../resources/test3.webp', 'test3');

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

</script>
<div>
  <span id="test"></span>
  <span id="test2"></span>
  <span id="test3"></span>
</div>
<div id="results"></div>
</body>
</html>