Saving last connection time in Observatory settings

runtime/observatory/lib/src/repositories/target.dart

 // Copyright (c) 2016, 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 repositories;
 
 class TargetChangeEvent implements M.TargetChangeEvent {
   final TargetRepository repository;
   TargetChangeEvent(this.repository);
 }
@@ skipping 29 matching lines @@
     _onChange.add(new TargetChangeEvent(this));
     _store();
   }
 
   Iterable<SC.WebSocketVMTarget> list() => _list;
 
   void setCurrent(M.Target t) {
     SC.WebSocketVMTarget target = t as SC.WebSocketVMTarget;
     if (!_list.contains(target)) return;
     current = target;
+    current.lastConnectionTime = new DateTime.now().millisecondsSinceEpoch;
     _onChange.add(new TargetChangeEvent(this));
+    _store();
   }
 
   void delete(o) {
     if (_list.remove(o)) {
       if (o == current) {
         current = null;
       }
       _onChange.add(new TargetChangeEvent(this));
       _store();
     }
@@ skipping 32 matching lines @@
       // We are running as JavaScript, use the same host that Observatory has
       // been loaded from.
       return 'ws://${window.location.host}/ws';
     } else {
       // Otherwise, assume we are running from Dart Editor and want to connect
       // to the default host.
       return 'ws://localhost:8181/ws';
     }
   }
 }