renderContents_(response) {
    var elem = this.getElement();
    goog.soy.renderElement(elem, templates.contentFrame, {
      label: chrome.i18n.getMessage('extName'),
      content: response.content || this.pgpMessage_,
      error: response.error
    });
    var styles = elem.querySelector('link');
    styles.href = chrome.runtime.getURL('glass_styles.css');
  }
Renders the contents of the looking glass.
@param {messages.ApiResponse} response The response from the extension to
    render.
@private