image_decoder_reentrant_decode.html

<!DOCTYPE html>
<title>basic image decoding</title>
<canvas width="128" height="128"></canvas>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
async_test(function(t) {
  let TEST_FILE = "/misc/resources/animated-gif-with-offsets.gif";
  fetch(TEST_FILE).then(t.step_func(response => {
    let decoder = new ImageDecoder({data: response.body, type: "image/gif"})

    let count = 0;
    Object.defineProperty(Object.prototype, "then", { get() {
      if (count++ == 0) {
        for (var i = 0; i < 4; i++)
          decoder.decode({frameIndex: 2}).then(() => {});
        decoder.decode({frameIndex: 3}).then(t.step_func_done());
      }
    }});

    decoder.decode({frameIndex: 0}).then(() => {});
    decoder.decode({frameIndex: 1}).then(() => {});
  })).catch(t.unreached_func());
});
</script>

chromium/third_party/blink/web_tests/http/tests/webcodecs/image_decoder_reentrant_decode.html