Method AddObserver

shell/browser/api/electron_api_web_contents.h:395–397

  [[nodiscard]] WebContentsZoomController* GetZoomController() const;

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