anchor.diff:  
     Future shareAnon({String summary: ""}) {
       return gistLoader
  -        .createAnon(mutableGist.createGist(summary: summary))
  -        .then((Gist newGist) {
  +    .createAnon(mutableGist.createGist(summary: summary))
  +    .then((Gist newGist) {
         editableGist.setBackingGist(newGist);
         overrideNextRoute(newGist);
         router.go('gist', {'gist': newGist.id});
  
positive.code: 
      var input = new CompileRequest()..source = context.dartSource;
      dartServices
          .compile(input)
          .timeout(longServiceCallTimeout)
          .then((CompileResponse response) {
        ga.sendTiming('action-perf', "compilation-e2e",
            compilationTimer.elapsedMilliseconds);
  
        _autoSwitchOutputTab();
  
  
negative.code:     Timer.run(() => _performAnalysis());
      _clearOutput();
    }
  
    Future showHome(RouteEnterEvent event) async {
      // Don't auto-run if we're re-loading some unsaved edits; the gist might
      // have halting issues (#384).
      bool loadedFromSaved = false;
      Uri url = Uri.parse(window.location.toString());
      if (url.hasQuery &&
      url.queryParameters['id'] != null &&
      isLegalGistId(url.queryParameters['id'])) {
        _showGist(url.queryParameters['id']);
      } else if (url.hasQuery && url.queryParameters['export'] != null) {
        UuidContainer requestId = new UuidContainer()..uuid=url.queryParameters['export'];
  