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
if (name == "appData")
    return brightray::DIR_APP_DATA;
  else if (name == "userData")
    return brightray::DIR_USER_DATA;
  else if (name == "cache")
    return brightray::DIR_CACHE;
  else if (name == "userCache")
    return brightray::DIR_USER_CACHE;
  else if (name == "home")
    return base::DIR_HOME;
  else if (name == "temp")
    return base::DIR_TEMP;
  else if (name == "userDesktop" || name == "desktop")
    return base::DIR_USER_DESKTOP;
  else if (name == "exe")
    return base::FILE_EXE;
  else if (name == "module")
    return base::FILE_MODULE;