There's no simple, cross-platform way to register protocol handlers in Electron. Every OS requires a different solution. This seems like something that Electron should smooth over.

There's already a W3C API for this: [`Navigator.registerProtocolHandler`](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/registerProtocolHandler). Can Electron implement it?

atom/browser/api/atom_api_app.cc
return ui::win::IsAeroGlassEnabled();
}
#endif
bool App::MakeSingleInstance(
    const ProcessSingleton::NotificationCallback& callback) {
  if (process_singleton_.get())
    return false;
  base::FilePath user_dir;
  PathService::Get(brightray::DIR_USER_DATA, &user_dir);
  process_singleton_.reset(new ProcessSingleton(
      user_dir, base::Bind(NotificationCallbackWrapper, callback)));
  switch (process_singleton_->NotifyOtherProcessOrCreate()) {
    case ProcessSingleton::NotifyResult::LOCK_ERROR:
    case ProcessSingleton::NotifyResult::PROFILE_IN_USE:
    case ProcessSingleton::NotifyResult::PROCESS_NOTIFIED:
      process_singleton_.reset();
      return true;
    case ProcessSingleton::NotifyResult::PROCESS_NONE:
    default:  
      return false;
  }
}
mate::ObjectTemplateBuilder App::GetObjectTemplateBuilder(
    v8::Isolate* isolate) {
  auto browser = base::Unretained(Browser::Get());
  return mate::ObjectTemplateBuilder(isolate)
      .SetMethod("quit", base::Bind(&Browser::Quit, browser))
      .SetMethod("exit", base::Bind(&Browser::Exit, browser))
      .SetMethod("focus", base::Bind(&Browser::Focus, browser))
      .SetMethod("getVersion", base::Bind(&Browser::GetVersion, browser))