Automatically fetch timeline when timeline page is loaded

runtime/observatory/lib/src/elements/timeline_page.dart

Index: runtime/observatory/lib/src/elements/timeline_page.dart
diff --git a/runtime/observatory/lib/src/elements/timeline_page.dart b/runtime/observatory/lib/src/elements/timeline_page.dart
index cdcb1d7ddaf60d3dbfc10557b2dc682959071da4..cc66f9a313a51ad08226fee421916a3c44e7bf53 100644
--- a/runtime/observatory/lib/src/elements/timeline_page.dart
+++ b/runtime/observatory/lib/src/elements/timeline_page.dart
@@ -8,6 +8,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:html';
 import 'observatory_element.dart';
+import 'package:observatory/elements.dart';
 import 'package:observatory/service_html.dart';
 import 'package:polymer/polymer.dart';
 
@@ -20,6 +21,9 @@ class TimelinePageElement extends ObservatoryElement {
     super.attached();
     _resizeSubscription = window.onResize.listen((_) => _updateSize());
     _updateSize();
+    // Click refresh button.
+    NavRefreshElement refreshButton = $['refresh'];
+    refreshButton.buttonClick(null, null, null);
   }
 
   detached() {