* Electron version: 1.4.4
* Operating system: win10

Hi,
Example described [here](https://github.com/electron/electron/blob/master/docs/api/global-shortcut.md) works with v1.4.0 but doesn't seem to work with v1.4.4 or v1.4.5.  Method `globalShortcut.isRegistered ` returns true, but the callback isn't called. 

Thanks!
atom/browser/api/atom_api_system_preferences.h
void InitializeWindow();
  
  void OnSysColorChange() override;
#elif defined(OS_MACOSX)
  using NotificationCallback = base::Callback<
    void(const std::string&, const base::DictionaryValue&)>;
  void PostNotification(const std::string& name,
                        const base::DictionaryValue& user_info);
  void PostLocalNotification(const std::string& name,
                             const base::DictionaryValue& user_info);
  int SubscribeNotification(const std::string& name,
                            const NotificationCallback& callback);
  void UnsubscribeNotification(int id);
  int SubscribeLocalNotification(const std::string& name,
                                 const NotificationCallback& callback);
  void UnsubscribeLocalNotification(int request_id);
  v8::Local<v8::Value> GetUserDefault(const std::string& name,
                                      const std::string& type);
  void SetUserDefault(const std::string& name,
                      const std::string& type,
                      mate::Arguments* args);
  bool IsSwipeTrackingFromScrollEventsEnabled();
#endif
  bool IsDarkMode();
  bool IsInvertedColorScheme();
 protected:
  explicit SystemPreferences(v8::Isolate* isolate);
  ~SystemPreferences() override;
#if defined(OS_MACOSX)
  void DoPostNotification(const std::string& name,