Converted general-error tag

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 66 matching lines @@
   bool canVisit(Uri uri) => uri.path == path;
 }
 
 /// Error page for unrecognized paths.
 class ErrorPage extends Page {
   ErrorPage(app) : super(app);
 
   void onInstall() {
     if (element == null) {
       // Lazily create page.
-      element = new Element.tag('general-error');
+      element = new GeneralErrorElement(app.notifications, queue: app.queue);
     }
   }
 
   void _visit(Uri uri) {
     assert(element != null);
     assert(canVisit(uri));
 
-    /*
-    if (uri.path == '') {
-      // Nothing requested.
-      return;
-    }
-    */
-
-    if (element != null) {
-      GeneralErrorElement serviceElement = element;
-      serviceElement.message = "Path '${uri.path}' not found";
-    }
+    (element as GeneralErrorElement).message = "Path '${uri.path}' not found";
   }
 
   /// Catch all.
   bool canVisit(Uri uri) => true;
 }
 
 /// Top-level vm info page.
 class VMPage extends SimplePage {
   VMPage(app) : super('vm', 'service-view', app);
 
@@ skipping 360 matching lines @@
     assert(element != null);
   }
 
   void _visit(Uri uri) {
     assert(element != null);
     assert(canVisit(uri));
   }
 
   bool canVisit(Uri uri) => uri.path == 'timeline';
 }