chromium/third_party/blink/web_tests/external/wpt/mediacapture-fromelement/HTMLCanvasElement-getImageData-noframe.html

<!DOCTYPE html>
<html>
<body>
<canvas id="canvas"></canvas>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script>
promise_test(async t => {
  const canvas = document.getElementById("canvas");
  const ctx = canvas.getContext("2d");
  const stream = canvas.captureStream();
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));

  const video = document.createElement("video");
  video.srcObject = stream;

  ctx.getImageData(0, 0, canvas.width, canvas.height);

  assert_equals(video.readyState, video.HAVE_NOTHING,
    "Video element was just created");

  // Wait a bit so the video element can update readyState in case of a frame.
  await new Promise(r => t.step_timeout(r, 100));

  assert_equals(video.readyState, video.HAVE_NOTHING,
    "Video element did not get a frame from the canvas");
}, "CanvasRenderingContext2D.getImageData() does not lead to a frame being captured");
</script>
</body>
</html>