* 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
TopLevelWindow::SetBackgroundColor(color_name);
  auto* view = web_contents()->GetRenderWidgetHostView();
  if (view)
    view->SetBackgroundColor(ParseHexColor(color_name));
}
void BrowserWindow::SetBrowserView(v8::Local<v8::Value> value) {
  TopLevelWindow::SetBrowserView(value);
#if defined(OS_MACOSX)
  UpdateDraggableRegions(nullptr, draggable_regions_);
#endif
}
void BrowserWindow::SetVibrancy(mate::Arguments* args) {
  std::string type;
  args->GetNext(&type);
  auto* render_view_host = web_contents()->GetRenderViewHost();
  if (render_view_host) {
    auto* impl = content::RenderWidgetHostImpl::FromID(
        render_view_host->GetProcess()->GetID(),
        render_view_host->GetRoutingID());
    if (impl)
      impl->SetBackgroundOpaque(type.empty() ? !window_->transparent() : false);
  }
  TopLevelWindow::SetVibrancy(args);
}
void BrowserWindow::FocusOnWebView() {