insertMessageIntoPage_(origin) {
    var textArea = this.getElement().querySelector('textarea');
    var recipients = this.chipHolder_.getSelectedUids();
    var subject = goog.dom.getElement(constants.ElementId.SUBJECT) ?
        goog.dom.getElement(constants.ElementId.SUBJECT).value :
        undefined;
    var prompt = /** @type {e2e.ext.ui.Prompt} */ (this.getParent());
    var shouldSend = false;
    var content = this.getContent();
    if (content && this.canSend_(content.origin)) {
      shouldSend = true;
    }
    prompt.getHelperProxy().updateSelectedContent(
        textArea.value, recipients, origin, shouldSend,
        goog.partial(goog.dispose, this.getParent()),
        goog.bind(this.errorCallback_, this), subject);
  }
Inserts the encrypted content into the page.
@param {string} origin The web origin for which the PGP action is
    performed.
@private