* 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_window.cc
auto window = static_cast<NativeWindowViews*>(window_.get());
  return window->taskbar_host().SetThumbnailClip(
      window_->GetAcceleratedWidget(), region);
}
bool Window::SetThumbnailToolTip(const std::string& tooltip) {
  auto window = static_cast<NativeWindowViews*>(window_.get());
  return window->taskbar_host().SetThumbnailToolTip(
      window_->GetAcceleratedWidget(), tooltip);
}
void Window::SetAppDetails(const mate::Dictionary& options) {
  base::string16 app_id;
  base::FilePath app_icon_path;
  int app_icon_index = 0;
  base::string16 relaunch_command;
  base::string16 relaunch_display_name;
  options.Get("appId", &app_id);
  options.Get("appIconPath", &app_icon_path);
  options.Get("appIconIndex", &app_icon_index);
  options.Get("relaunchCommand", &relaunch_command);
  options.Get("relaunchDisplayName", &relaunch_display_name);
  ui::win::SetAppDetailsForWindow(
      app_id, app_icon_path, app_icon_index,
      relaunch_command, relaunch_display_name,
      window_->GetAcceleratedWidget());
}
#endif
#if defined(TOOLKIT_VIEWS)
void Window::SetIcon(mate::Handle<NativeImage> icon) {