Derived from: humanReadablePane .. share code?
function (subject, myDocument) {
    var div = myDocument.createElement('div')
    var kb = UI.store

    //  @@ When we can, use CSP to turn off scripts within the iframe
    div.setAttribute('class', 'docView')
    var iframe = myDocument.createElement('IFRAME')
    iframe.setAttribute('src', subject.uri) // allow-same-origin
    iframe.setAttribute('class', 'doc')

    var cts = kb.fetcher.getHeader(subject.doc(), 'content-type')
    var ct = cts ? cts[0] : null
    if (ct) {
      console.log('dokieliPane: c-t:' + ct)
    } else {
      console.log('dokieliPane: unknown content-type?')
    }

    // @@ NOte beflow - if we set ANY sandbox, then Chrome and Safari won't display it if it is PDF.
    // https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe
    // You can;'t have any sandbox and allow plugins.
    // We could sandbox only HTML files I suppose.
    // HTML5 bug: https://lists.w3.org/Archives/Public/public-html/2011Jun/0330.html

    // iframe.setAttribute('sandbox', 'allow-same-origin allow-forms'); // allow-scripts ?? no documents should be static

    iframe.setAttribute('style', 'resize = both; height: 40em; width:40em;') // @@ improve guess
    //        iframe.setAttribute('height', '480')
    //        iframe.setAttribute('width', '640')
    var tr = myDocument.createElement('tr')
    tr.appendChild(iframe)
    div.appendChild(tr)
    return div
  }