As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
return new NativeWindowClientView(widget, root_view_.get(), this);
}
std::unique_ptr<views::NonClientFrameView>
NativeWindowViews::CreateNonClientFrameView(views::Widget* widget) {
#if defined(OS_WIN)
  auto frame_view = std::make_unique<WinFrameView>();
  frame_view->Init(this, widget);
  return frame_view;
#else
  if (has_frame()) {
    return std::make_unique<NativeFrameView>(this, widget);
  } else {
    auto frame_view = std::make_unique<FramelessView>();
    frame_view->Init(this, widget);
    return frame_view;
  }
#endif
}
void NativeWindowViews::OnWidgetMove() {