* 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_->IsAlwaysOnTop();
}
void NativeWindowViews::Center() {
  window_->CenterWindow(GetSize());
}
void NativeWindowViews::SetTitle(const std::string& title) {
  title_ = title;
  window_->UpdateWindowTitle();
}
std::string NativeWindowViews::GetTitle() {
  return title_;
}
void NativeWindowViews::FlashFrame(bool flash) {
#if defined(OS_WIN)
  
  if (!flash) {
    FLASHWINFO fwi;
    fwi.cbSize = sizeof(fwi);
    fwi.hwnd = GetAcceleratedWidget();
    fwi.dwFlags = FLASHW_STOP;
    fwi.uCount = 0;
    FlashWindowEx(&fwi);
    return;
  }
#endif
  window_->FlashFrame(flash);
}
void NativeWindowViews::SetSkipTaskbar(bool skip) {