* Electron version: 1.7.6
* Operating system: MacOS High Sierra GM

### Expected behavior

Title bar should not be invisible

![screen shot 2017-09-14 at 11 22 04 am](https://user-images.githubusercontent.com/320654/30441406-f34fe61a-993e-11e7-8592-244e50a92bb9.png)

### Actual behavior

Title bar is invisible

### How to reproduce
```
  mainWindow = new BrowserWindow({
      vibrancy: 'light',
      titleBarStyle: 'hiddenInset',
      width: 800,
      height: 600
  })
```

```
 $ git clone git@github.com:gerges/electron-quick-start.git -b  issue/invisible-titlebar
 $ npm install
 $ npm run start
```

atom/browser/native_window_mac.h
#ifndef ATOM_BROWSER_NATIVE_WINDOW_MAC_H_
#define ATOM_BROWSER_NATIVE_WINDOW_MAC_H_
#import <Cocoa/Cocoa.h>
#include <string>
#include <vector>
#include "atom/browser/native_window.h"
#include "base/mac/scoped_nsobject.h"
#include "content/public/browser/render_widget_host.h"
@class AtomNSWindow;