### Preflight Checklist

* [x] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
* [x] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
* [x] I have searched the issue tracker for an issue that matches the one I want to file, without success.

### Issue Details

It would appear that `app.focus()` stopped working in Electron 6, and remains broken in Electron 8.

* **Electron Version:**
  * 8.0.3
* **Operating System:**
  * macOS
* **Last Known Working Electron version:**
  * 5.0.13

### Expected Behavior
`app.focus()` should bring the application to the foreground.

### Actual Behavior
`app.focus()` does nothing.

### To Reproduce

Fiddle: https://gist.github.com/a772265b312329e3f3bc1feb7b6aff7d

1) Start this fiddle.
2) As soon as the window pops up, select another application so that Electron is in the background.
3) Within 5 seconds, the app will attempt to focus itself to no avail.

shell/browser/browser.h
void AddRecentDocument(const base::FilePath& path);
  
  void ClearRecentDocuments();
  
  void SetAppUserModelID(const base::string16& name);
  
  bool RemoveAsDefaultProtocolClient(const std::string& protocol,
                                     gin_helper::Arguments* args);
  
  bool SetAsDefaultProtocolClient(const std::string& protocol,
                                  gin_helper::Arguments* args);
  
  bool IsDefaultProtocolClient(const std::string& protocol,
                               gin_helper::Arguments* args);
  base::string16 GetApplicationNameForProtocol(const GURL& url);
  
  bool SetBadgeCount(int count);
  int GetBadgeCount();
  
  struct LoginItemSettings {
    bool open_at_login = false;
    bool open_as_hidden = false;
    bool restore_state = false;
    bool opened_at_login = false;
    bool opened_as_hidden = false;
    base::string16 path;
    std::vector<base::string16> args;
    LoginItemSettings();
    ~LoginItemSettings();
    LoginItemSettings(const LoginItemSettings&);