### 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_win.cc
if (base::win::GetVersion() >= base::win::Version::WIN8) {
    base::string16 application_name = GetAppForProtocolUsingAssocQuery(url);
    if (!application_name.empty())
      return application_name;
  }
  return GetAppForProtocolUsingRegistry(url);
}
bool Browser::SetBadgeCount(int count) {
  return false;
}
void Browser::SetLoginItemSettings(LoginItemSettings settings) {
  base::string16 keyPath = L"Software\\Microsoft\\Windows\\CurrentVersion\\Run";
  base::win::RegKey key(HKEY_CURRENT_USER, keyPath.c_str(), KEY_ALL_ACCESS);
  if (settings.open_at_login) {
    base::string16 exe = settings.path;
    if (FormatCommandLineString(&exe, settings.args)) {
      key.WriteValue(GetAppUserModelID(), exe.c_str());
    }
  } else {
    key.DeleteValue(GetAppUserModelID());
  }
}
Browser::LoginItemSettings Browser::GetLoginItemSettings(