Would it be possible to add methods and/or events to expose the visibility state of Menu instances? For example methods like `Menu#isVisible()` and `Menu#isHidden()` and events like "show" and "hide".
shell/browser/ui/tray_icon.h
void RemoveObserver(TrayIconObserver* obs) { observers_.RemoveObserver(obs); }
  void NotifyClicked(const gfx::Rect& = gfx::Rect(),
                     const gfx::Point& location = gfx::Point(),
                     int modifiers = 0);
  void NotifyDoubleClicked(const gfx::Rect& = gfx::Rect(), int modifiers = 0);