code: private static XeSource make(final Request req, final CharSequence app,
          final CharSequence rel, final CharSequence redir) throws IOException {
          return new XeLink(
              rel,
              new Href("https://accounts.google.com/o/oauth2/auth")
                  .with("client_id", app)
                  .with("redirect_uri", redir)
                  .with("response_type", "code")
                  .with("state", new RqHref.Base(req).href())
                  .with(
                      "scope",
                      "https://www.googleapis.com/auth/userinfo.profile"
                  )
          );
      }
docs: Ctor.
  @param req Request
  @param app Google application ID
  @param rel Related
  @param redir Redirect URI
  @return Source
  @throws IOException If fails
  @since 0.14
  @checkstyle ParameterNumberCheck (4 lines)