### 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
base::Value dict(base::Value::Type::DICTIONARY);
  std::string aboutMessage = "";
  gfx::ImageSkia image;
  
  std::unique_ptr<FileVersionInfo> exe_info = FetchFileVersionInfo();
  dict.SetStringKey("applicationName", exe_info->file_description());
  dict.SetStringKey("applicationVersion", exe_info->product_version());
  if (about_panel_options_.is_dict()) {
    dict.MergeDictionary(&about_panel_options_);
  }
  std::vector<std::string> stringOptions = {
      "applicationName", "applicationVersion", "copyright", "credits"};
  const std::string* str;
  for (std::string opt : stringOptions) {
    if ((str = dict.FindStringKey(opt))) {
      aboutMessage.append(*str).append("\r\n");
    }
  }
  if ((str = dict.FindStringKey("iconPath"))) {
    base::FilePath path = base::FilePath::FromUTF8Unsafe(*str);
    electron::util::PopulateImageSkiaRepsFromPath(&image, path);
  }
  electron::MessageBoxSettings settings = {};
  settings.message = aboutMessage;
  settings.icon = image;
  settings.type = electron::MessageBoxType::kInformation;
  electron::ShowMessageBoxSync(settings);
}
void Browser::SetAboutPanelOptions(base::DictionaryValue options) {