As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
const gfx::Rect& bounds) {
  if (changed_widget != widget())
    return;
  
  
  const auto new_bounds = GetBounds();
  if (widget_size_ != new_bounds.size()) {
    int width_delta = new_bounds.width() - widget_size_.width();
    int height_delta = new_bounds.height() - widget_size_.height();
    for (NativeBrowserView* item : browser_views()) {
      auto* native_view = static_cast<NativeBrowserViewViews*>(item);
      native_view->SetAutoResizeProportions(widget_size_);
      native_view->AutoResize(new_bounds, width_delta, height_delta);
    }
    NotifyWindowResize();
    widget_size_ = new_bounds.size();
  }
}
void NativeWindowViews::OnWidgetDestroying(views::Widget* widget) {
#if defined(OS_LINUX)
  aura::Window* window = GetNativeWindow();
  if (window)
    window->RemovePreTargetHandler(this);
#endif
}
void NativeWindowViews::DeleteDelegate() {