Add persistent handles to service protocol and Observatory UI

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

Index: runtime/observatory/lib/src/app/application.dart
diff --git a/runtime/observatory/lib/src/app/application.dart b/runtime/observatory/lib/src/app/application.dart
index bda98c0df942e090aaa97622c096b57f2ab335d8..644b65912cb20d2426e75cf0062dfdc76fdc44b0 100644
--- a/runtime/observatory/lib/src/app/application.dart
+++ b/runtime/observatory/lib/src/app/application.dart
@@ -139,6 +139,7 @@ class ObservatoryApplication extends Observable {
     _pageRegistry.add(new IsolateReconnectPage(this));
     _pageRegistry.add(new ErrorViewPage(this));
     _pageRegistry.add(new MetricsPage(this));
+    _pageRegistry.add(new PersistentHandlesPage(this));
     _pageRegistry.add(new PortsPage(this));
     _pageRegistry.add(new LoggingPage(this));
     _pageRegistry.add(new TimelinePage(this));