partitioned-webkitTemporaryStorage-query-usage-helper-frame.html

<!DOCTYPE html>
<meta name=help href="https://privacycg.github.io/storage-partitioning/">
<title>Helper frame</title>

<script>
  const usageDetails = () => {
    return new Promise((resolve, reject) => {
      navigator.webkitTemporaryStorage.queryUsageAndQuota(
        (usage, quota) => resolve({ usage: usage, quota: quota }), reject)
    }).then(details => details).catch(error => { throw error; });
  }

  let details = {};

  window.addEventListener("message", async event => {
    if (event.data === "get-details") {
      details.source = "same-site";
      details.init = await usageDetails();
      event.source.postMessage(details, event.source.origin);
    }
  });

  window.addEventListener("load", async () => {
    if (parent.opener) {
      details.source = "cross-site";
      details.init = await usageDetails();
      parent.opener.postMessage(details, parent.opener.origin);
    }
  });
</script>

chromium/third_party/blink/web_tests/wpt_internal/storage/quota/resources/partitioned-webkitTemporaryStorage-query-usage-helper-frame.html