Fix condition.

client/dart.js

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Bootstrap support for Dart scripts on the page as this script.
 if (navigator.webkitStartDart) {
-  if (navigator.webkitStartDart()) {
+  if (!navigator.webkitStartDart()) {
     document.body.innerHTML = 'This build has expired.  Please download a new Dartium at http://www.dartlang.org/dartium/index.html';
   }
 } else {
   // TODO:
   // - Support in-browser compilation.
   // - Handle inline Dart scripts.
   window.addEventListener("DOMContentLoaded", function (e) {
     // Fall back to compiled JS. Run through all the scripts and
     // replace them if they have a type that indicate that they source
     // in Dart code.
@@ skipping 20 matching lines @@
           } else {
             script.src = scripts[i].src + '.js';
           }
           var parent = scripts[i].parentNode;
           parent.replaceChild(script, scripts[i]);
         }
       }
     }
   }, false);
 }