If the VM page fails to load, route to the VM connect page

runtime/observatory/lib/src/app/page.dart

 // Copyright (c) 2014, 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 app;
 
 class IsolateNotFound implements Exception {
   String isolateId;
   IsolateNotFound(this.isolateId);
   String toString() => "IsolateNotFound: $isolateId";
@@ skipping 104 matching lines @@
 
   void _visit(Uri uri) {
     super._visit(uri);
     app.vm.reload().then((vm) {
       if (element != null) {
         ServiceObjectViewElement serviceElement = element;
         serviceElement.object = vm;
       }
     }).catchError((e, stack) {
       Logger.root.severe('VMPage visit error: $e');
+      // Reroute to vm-connect.
+      app.locationManager.go(app.locationManager.makeLink('/vm-connect'));
     });
   }
 }
 
 class FlagsPage extends SimplePage {
   FlagsPage(app) : super('flags', 'flag-list', app);
 
   void _visit(Uri uri) {
     super._visit(uri);
     app.vm.getFlagList().then((flags) {
@@ skipping 301 matching lines @@
     assert(element != null);
   }
 
   void _visit(Uri uri) {
     assert(element != null);
     assert(canVisit(uri));
   }
 
   bool canVisit(Uri uri) => uri.path == 'timeline';
 }