* Electron version: 1.6.15
* Operating system: Linux

### Expected behavior

Open a `BrowserWindow` with passed options

### Actual behavior

  - Usually a Segmentation fault.
  - Sometimes `[12843:0100/000000.043847:FATAL:zygote_linux.cc(479)] Failed to synchronise with parent zygote process`
  - Sometimes `[12819:0100/000000.719122:FATAL:zygote_linux.cc(509)] Check failed: len > 0 (0 vs. 0)`

### How to reproduce

I'm still working on making a smaller reproduction case. The issue goes away with small tweaks.

1. Starting from https://github.com/daurnimator/fengari-electron-example
2. Modify main.lua to contain:
```lua
local js = require "js"
local electron = require "electron"

electron.app:on("ready", function()
	local win = js.new(electron.BrowserWindow, js.createproxy({
		backgroundColor = '#2e2c29';
	}, "object"))
	win:loadURL("https://fengari.io")
end)
```

atom/browser/api/atom_api_web_contents.cc
set_ignore_menu_shortcuts(ignore);
}
void WebContents::SetAudioMuted(bool muted) {
  web_contents()->SetAudioMuted(muted);
}
bool WebContents::IsAudioMuted() {
  return web_contents()->IsAudioMuted();
}
void WebContents::Print(mate::Arguments* args) {
  PrintSettings settings = { false, false, base::string16() };
  if (args->Length() >= 1 && !args->GetNext(&settings)) {
    args->ThrowError();
    return;
  }
  auto print_view_manager_basic_ptr =
      printing::PrintViewManagerBasic::FromWebContents(web_contents());
  if (args->Length() == 2) {
    base::Callback<void(bool)> callback;
    if (!args->GetNext(&callback)) {
      args->ThrowError();
      return;
    }
    print_view_manager_basic_ptr->SetCallback(callback);
  }
  print_view_manager_basic_ptr->PrintNow(web_contents()->GetMainFrame(),
               settings.silent,
               settings.print_background,
               settings.device_name);
}
std::vector<printing::PrinterBasicInfo> WebContents::GetPrinterList() {