Timeline service protocol support with Observatory UI

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 407 matching lines @@
   void _visit(Uri uri) {
     assert(element != null);
     assert(canVisit(uri));
     app.vm.getIsolate(uri.queryParameters['isolateId']).then((i) {
       (element as MetricsPageElement).isolate = i;
     });
   }
 
   bool canVisit(Uri uri) => uri.path == 'metrics';
 }
+
+class TimelinePage extends Page {
+  TimelinePage(app) : super(app);
+
+  void onInstall() {
+    if (element == null) {
+      element = new Element.tag('timeline-page');
+    }
+    assert(element != null);
+  }
+
+  void _visit(Uri uri) {
+    assert(element != null);
+    assert(canVisit(uri));
+  }
+
+  bool canVisit(Uri uri) => uri.path == 'timeline';
+}