index.html

<!DOCTYPE html>
<html lang=en>
  <head>
    <script src=https://apis.google.com/js/api.js></script>
    <style>
      iframe {
        border: none;
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
      }
    </style>
  </head>
  <body>
    <iframe id=content></iframe>
    <script>
      const params = new URLSearchParams(document.location.search)
      gapi.load('client', () => {
        gapi.client.init({
          apiKey: params.get('key'),
          discoveryDocs: ['https://www.googleapis.com/discovery/v1/apis/drive/v3/rest']
        }).then(() => {
          gapi.client.drive.files.get({
            fileId: params.get('id'),
            alt: 'media'
          }).then(response => {
            const doc = document.getElementById('content').contentWindow.document
            doc.open()
            doc.write(response.body)
            doc.close()
          })
        })
      })
    </script>
  </body>
</html>