* Electron version: 1.4.14
* Operating system: Windows 8.1

### Expected behavior

A fullscreen transparent window should be transparent.

### Actual behavior

The window is not transparent (has a white background).

### How to reproduce

```
electron.app.on("ready", function () {
    var win = new BrowserWindow({
        show: true,
        frame: false,
        fullscreen: true,
        transparent: true
    });
});
```

Refs https://github.com/electron/electron/issues/8321#issuecomment-273615701


atom/browser/native_window_views.cc
NativeWindow::SetParentWindow(parent);
#if defined(USE_X11)
  XDisplay* xdisplay = gfx::GetXDisplay();
  XSetTransientForHint(
      xdisplay, GetAcceleratedWidget(),
      parent? parent->GetAcceleratedWidget() : DefaultRootWindow(xdisplay));
#elif defined(OS_WIN) && defined(DEBUG)
  
  
  if (parent) {
    ::SetParent(GetAcceleratedWidget(), parent->GetAcceleratedWidget());
    views::Widget::ReparentNativeView(GetNativeWindow(),
                                      parent->GetNativeWindow());
    wm::AddTransientChild(parent->GetNativeWindow(), GetNativeWindow());
  } else {
    if (!GetNativeWindow()->parent())
      return;
    ::SetParent(GetAcceleratedWidget(), NULL);
    views::Widget::ReparentNativeView(GetNativeWindow(), nullptr);
    wm::RemoveTransientChild(GetNativeWindow()->parent(), GetNativeWindow());
  }
#endif
}
gfx::NativeWindow NativeWindowViews::GetNativeWindow() {