* 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
return window_->IsVisible();
}
bool NativeWindowViews::IsEnabled() {
#if defined(OS_WIN)
  return ::IsWindowEnabled(GetAcceleratedWidget());
#elif defined(USE_X11)
  return !event_disabler_.get();
#endif
}
void NativeWindowViews::Maximize() {
#if defined(OS_WIN)
  
  if (!(::GetWindowLong(GetAcceleratedWidget(), GWL_STYLE) & WS_THICKFRAME)) {
    restore_bounds_ = GetBounds();
    auto display =
        display::Screen::GetScreen()->GetDisplayNearestPoint(GetPosition());
    SetBounds(display.work_area(), false);
    return;
  }
#endif
  if (IsVisible())
    window_->Maximize();
  else
    window_->native_widget_private()->ShowWithWindowState(
        ui::SHOW_STATE_MAXIMIZED);
}
void NativeWindowViews::Unmaximize() {