Update the navbar in the observatory

runtime/bin/vmservice/client/lib/src/observatory/location_manager.dart

 // Copyright (c) 2013, 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.
 
 part of observatory;
 
 /// The LocationManager class observes and parses the hash ('#') portion of the
 /// URL in window.location. The text after the '#' is used as the request
 /// string for the VM service.
 class LocationManager extends Observable {
@@ skipping 47 matching lines @@
   /// if none is present in window.location.
   String currentIsolateId() {
     var prefix = currentIsolateAnchorPrefix();
     if (prefix == null) {
       return '';
     }
     // Chop off the '/#'.
     return prefix.substring(2);
   }
 
-  Isolate currentIsolate() {
+  @observable Isolate currentIsolate() {
     var id = currentIsolateId();
     if (id == '') {
       return null;
     }
     return _application.isolateManager.getIsolate(id);
   }
 
   /// If no anchor is set, set the default anchor and return true.
   /// Return false otherwise.
   bool setDefaultHash() {
@@ skipping 43 matching lines @@
   String relativeLink(String isolateId, String l) {
     return '#/$isolateId/$l';
   }
 
   /// Create a request for [l] on [isolateId].
   @observable
   String absoluteLink(String l) {
     return '#/$l';
   }
 }