As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
if (is_modal() && this->parent()) {
    auto* parent = this->parent();
    
    static_cast<NativeWindowViews*>(parent)->DecrementChildModals();
    
    parent->Focus(true);
  }
  NotifyWindowClosed();
}
views::View* NativeWindowViews::GetInitiallyFocusedView() {
  return focused_view_;
}
bool NativeWindowViews::CanResize() const {
  return resizable_;
}
bool NativeWindowViews::CanMaximize() const {
  return resizable_ && maximizable_;
}
bool NativeWindowViews::CanMinimize() const {
#if defined(OS_WIN)
  return minimizable_;
#elif defined(OS_LINUX)
  return true;
#endif
}
base::string16 NativeWindowViews::GetWindowTitle() const {