It's going to be removed from Chromium, see https://crbug.com/812523.

/cc @electron/code-owners 
shell/browser/api/electron_api_app.h
void OnBeforeQuit(bool* prevent_default) override;
  void OnWillQuit(bool* prevent_default) override;
  void OnWindowAllClosed() override;
  void OnQuit() override;
  void OnOpenFile(bool* prevent_default, const std::string& file_path) override;
  void OnOpenURL(const std::string& url) override;
  void OnActivate(bool has_visible_windows) override;
  void OnWillFinishLaunching() override;
  void OnFinishLaunching(const base::DictionaryValue& launch_info) override;
  void OnAccessibilitySupportChanged() override;
  void OnPreMainMessageLoopRun() override;
#if defined(OS_MACOSX)
  void OnWillContinueUserActivity(bool* prevent_default,
                                  const std::string& type) override;
  void OnDidFailToContinueUserActivity(const std::string& type,
                                       const std::string& error) override;
  void OnContinueUserActivity(bool* prevent_default,
                              const std::string& type,
                              const base::DictionaryValue& user_info) override;
  void OnUserActivityWasContinued(
      const std::string& type,
      const base::DictionaryValue& user_info) override;
  void OnUpdateUserActivityState(
      bool* prevent_default,
      const std::string& type,
      const base::DictionaryValue& user_info) override;
  void OnNewWindowForTab() override;
#endif
  
  void AllowCertificateError(