anchor.diff:  
     void _attemptToAquireGitHubToken() {
       // Remember all of our current query params.
  -    final curUrl = Uri.parse(window.location.toString());
  +    var curUrl = Uri.parse(window.location.toString());
       final params = Map<String, String?>.from(curUrl.queryParameters);
  +
  +    if (params.containsKey(queryParamRedirectBeforeLogin)) {
  +      // Remove the [queryParamRedirectBeforeLogin] parameter from the URL,
  +      // we have detected it (after redirect to `dartpad.dev`)
  +      // and now we are initiating the GitHub login.  We no longer needed it,
  +      // (and we want to prevent a 'loop').
  +      params.remove(queryParamRedirectBeforeLogin);
  +      curUrl = curUrl.replace(queryParameters: params);
  +    }
  +
       final jsonParams = json.encode(params);
   
  +    if (window.location.hostname != 'dartpad.dev') {
  +      // We have to START our login from `dartpad.dev` as that's where we
  +      // will be returning.  We add an additional query parameter
  +      // defined by [queryParamRedirectBeforeLogin] to indicate that we
  +      // should initiate the GitHub login when we arrive at `dartpad.dev`.
  +      // That way to the user it is 'transparent' and the login automatically
  +      // continues when they get there.
  +      params.addAll({queryParamRedirectBeforeLogin: 'true'});
  +      // Change scheme and port also in case those were different also.
  +      final newUrl = curUrl.replace(
  +          scheme: 'https',
  +          host: 'dartpad.dev',
  +          port: 443,
  +          queryParameters: params);
  +      window.location.href = newUrl.toString();
  +      return;
  +    }
       window.localStorage[localStorageKeyForQueryParamsPreOAuthRequest] =
           jsonParams;
   
  
positive.code:   GitHubUIController(this._playground) {
      _githubAuthController = GitHubAuthenticationController(
          Uri.parse(window.location.toString()), _playground.snackbar);
      initGitHubMenu();
      setupGithubGistListeners();
  
  
negative.code:     final params = Map<String, String?>.from(launchUri.queryParameters);
      final ghTokenFromUrl = params['gh'] ?? '';
      final ghScope = params['scope'] ?? '';
      delayedGitHubLoginRequested =
          (params[queryParamRedirectBeforeLogin] != null);
  
      if (delayedGitHubLoginRequested) {
        // A delayed GitHub login has been requested, as we must arrived from
        // a redirect from another dartpad url.  We return early here because
        // a login to GitHub is going to be automatically initiated immediately.
        return;
      }
  
      if (ghTokenFromUrl.isNotEmpty) {
        final String perAuthParamsJson =
  