* Electron Version: v3.0.0-beta.2
* Operating System (Platform and Version): macOS 10.13.5
* Last known working Electron version: v3.0.0-beta.1

**Expected Behavior**
Launching DevTools

**Actual behavior**
Electron crash with current dump:
```
Crashing on exception: *** -[__NSArrayM objectAtIndex:]: index 1 beyond bounds [0 .. 0]

Application Specific Backtrace 1:
0   CoreFoundation                      0x00007fff489d332b __exceptionPreprocess + 171
1   libobjc.A.dylib                     0x00007fff6fb41c76 objc_exception_throw + 48
2   CoreFoundation                      0x00007fff48a14634 _CFThrowFormattedException + 202
3   CoreFoundation                      0x00007fff488f2290 __CFStringDecodeByteStream3 + 0
4   Electron Framework                  0x000000010e7554c2 _ZN9brightray8IOThread7CleanUpEv + 2210
...
```

**Additional info** 
`BrowserWindow` should contain `titleBarStyle` with `hiddenInset` value.

Full dump attached to [link](https://github.com/electron/electron/files/2185677/dump.txt)

atom/browser/api/atom_api_browser_window.h
void OverrideNSWindowContentView();
#endif
  
  
  void UpdateDraggableRegions(content::RenderFrameHost* rfh,
                              const std::vector<DraggableRegion>& regions);
  
  std::unique_ptr<SkRegion> DraggableRegionsToSkRegion(
      const std::vector<DraggableRegion>& regions);
  
  void ScheduleUnresponsiveEvent(int ms);
  
  void NotifyWindowUnresponsive();
  
  void Cleanup();
  
  
  base::CancelableClosure window_unresponsive_closure_;
#if defined(OS_MACOSX)
  std::vector<DraggableRegion> draggable_regions_;
#endif
  v8::Global<v8::Value> web_contents_;
  api::WebContents* api_web_contents_;
  base::WeakPtrFactory<BrowserWindow> weak_factory_;
  DISALLOW_COPY_AND_ASSIGN(BrowserWindow);
};
}  
}  
#endif