Add expiration check into dart.js script.

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) {
-  navigator.webkitStartDart();
+  if (navigator.webkitStartDart()) {

[vsm, 2012/05/16 19:14:01]

Minor nit: I'd suggest changing failure from true to false.  I.e., it'd be more
intuitive to have webkitStartDart return false if it fails.

[Anton Muhin, 2012/05/17 14:20:28]

We need to think out landing process as if I change C++ implementation, people
we fresh builds will be told to upgrade, but there will be no warning to people
with outdated builds.

wdyt, should we change it or maybe leave it as is now?

On 2012/05/16 19:14:01, vsm wrote:

+    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.
     //
     //   <script type="application/dart" src="<file>.dart"></script>
@@ skipping 18 matching lines @@
           } else {
             script.src = scripts[i].src + '.js';
           }
           var parent = scripts[i].parentNode;
           parent.replaceChild(script, scripts[i]);
         }
       }
     }
   }, false);
 }