<!--
Thanks for opening an issue! A few things to keep in mind:

- The issue tracker is only for bugs and feature requests.
- Before reporting a bug, please try reproducing your issue against
  the latest version of Electron.
- If you need general advice, join our Slack: http://atom-slack.herokuapp.com
-->

* Electron version: 2.0.0-beta.3
* Operating system: Ubuntu 16.04.04 LTS

### Expected behavior

App menu should be visible

### Actual behavior

App menu is invisible

### How to reproduce

- Run `electron`
- Observe that the app menu is invisible. It is still possible to open submenus.

![screenshot from 2018-03-14 17-01-18](https://user-images.githubusercontent.com/19880051/37415303-7296c25e-27ab-11e8-8284-d213c8bf5230.png)

atom/browser/ui/views/menu_bar.cc
#include "atom/browser/ui/views/menu_bar.h"
#if defined(USE_X11)
#include "gtk/gtk.h"
#endif
#include "atom/browser/ui/views/menu_delegate.h"
#include "atom/browser/ui/views/submenu_button.h"
#include "ui/base/models/menu_model.h"
#include "ui/views/background.h"
#include "ui/views/layout/box_layout.h"
#if defined(OS_WIN)
#include "ui/gfx/color_utils.h"
#elif defined(USE_X11)
#include "chrome/browser/ui/libgtkui/skia_utils_gtk.h"
#endif
namespace atom {
namespace {
#if defined(USE_X11)
SkColor GdkRgbaToSkColor(const GdkRGBA& rgba) {
  return SkColorSetARGB(rgba.alpha * 255, rgba.red * 255, rgba.green * 255,
                        rgba.blue * 255);
}
SkColor GetStyleContextFgColor(GtkStyleContext* style_context,