* 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.cc
window_unresponsive_closure_.Cancel();
  Emit("responsive");
}
void BrowserWindow::RequestPreferredWidth(int* width) {
  *width = web_contents()->GetPreferredSize().width();
}
void BrowserWindow::OnCloseButtonClicked(bool* prevent_default) {
  
  
  
  *prevent_default = true;
  
  
  
  
  if (window_unresponsive_closure_.IsCancelled())
    ScheduleUnresponsiveEvent(5000);
  if (!web_contents())
    
    return;
  if (web_contents()->NeedToFireBeforeUnload())
    web_contents()->DispatchBeforeUnload();
  else
    web_contents()->Close();
}
void BrowserWindow::OnWindowClosed() {