  void RemoveObserver(ExtendedWebContentsObserver* obs) {
    // Trying to remove from an empty collection leads to an access violation
    if (!observers_.empty())
      observers_.RemoveObserver(obs);
  }
  void RemoveObserver(ExtendedWebContentsObserver* obs) {
     
    if (!observers_.empty())
      observers_.RemoveObserver(obs);
  }