showMenuInline_(menu) {
    var menuButton = this.getElementByClass(constants.CssClass.MENU_BUTTON);
    this.hideHeaderButtons_();
    menu.detach(menuButton);
    // Show the menu inline instead and restyle it.
    goog.dom.classlist.remove(menu.getElement(), 'goog-menu');
    goog.style.setStyle(
        menu.getElement(),
        {'display': 'block', 'outline': 'none', 'position': 'relative'});
  }
Show the menu in the prompt document inline, hiding the menu container
    button.
@param {!goog.ui.PopupMenu} menu Menu element.
@private