As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
if (IsMaximized())
    return ui::SHOW_STATE_MAXIMIZED;
  if (IsFullscreen())
    return ui::SHOW_STATE_FULLSCREEN;
  return ui::SHOW_STATE_NORMAL;
}
void NativeWindowViews::MoveBehindTaskBarIfNeeded() {
#if defined(OS_WIN)
  if (behind_task_bar_) {
    const HWND task_bar_hwnd = ::FindWindow(kUniqueTaskBarClassName, nullptr);
    ::SetWindowPos(GetAcceleratedWidget(), task_bar_hwnd, 0, 0, 0, 0,
                   SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE);
  }
#endif
  
}
NativeWindow* NativeWindow::Create(const gin_helper::Dictionary& options,
                                   NativeWindow* parent) {
  return new NativeWindowViews(options, parent);
}
}