Centralized event streams

runtime/observatory/lib/src/elements/nav/isolate_menu.dart

Index: runtime/observatory/lib/src/elements/nav/isolate_menu.dart
diff --git a/runtime/observatory/lib/src/elements/nav/isolate_menu.dart b/runtime/observatory/lib/src/elements/nav/isolate_menu.dart
index 3f0089ad33b5087864c74e46394f7ca9fd1c9ad8..d9f82c904f24615c6f229589b8fed47a5e015968 100644
--- a/runtime/observatory/lib/src/elements/nav/isolate_menu.dart
+++ b/runtime/observatory/lib/src/elements/nav/isolate_menu.dart
@@ -5,7 +5,7 @@
 import 'dart:html';
 import 'dart:async';
 import 'package:observatory/models.dart' as M
-  show IsolateRef, IsolateUpdateEvent;
+  show IsolateRef, EventRepository;
 import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
 import 'package:observatory/src/elements/helpers/tag.dart';
 import 'package:observatory/src/elements/helpers/uris.dart';
@@ -21,25 +21,27 @@ class NavIsolateMenuElement extends HtmlElement implements Renderable {
 
   Stream<RenderedEvent<NavIsolateMenuElement>> get onRendered => _r.onRendered;
 
-  Stream<M.IsolateUpdateEvent> _updates;
-  StreamSubscription _updatesSubscription;
-
   bool _last;
   M.IsolateRef _isolate;
+  M.EventRepository _events;
+  StreamSubscription _updatesSubscription;
+
   bool get last => _last;
   M.IsolateRef get isolate => _isolate;
+
   set last(bool value) => _last = _r.checkAndReact(_last, value);
 
   factory NavIsolateMenuElement(M.IsolateRef isolate,
-      Stream<M.IsolateUpdateEvent> updates, {bool last: false,
+      M.EventRepository events, {bool last: false,
       RenderingQueue queue}) {
     assert(isolate != null);
+    assert(events != null);
     assert(last != null);
     NavIsolateMenuElement e = document.createElement(tag.name);
     e._r = new RenderingScheduler(e, queue: queue);
     e._isolate = isolate;
     e._last = last;
-    e._updates = updates;
+    e._events = events;
     return e;
   }
 
@@ -51,12 +53,10 @@ class NavIsolateMenuElement extends HtmlElement implements Renderable {
   @override
   void attached() {
     super.attached();
-    assert(_isolate != null);
-    assert(_updates != null);
+    _updatesSubscription = _events.onIsolateUpdate
+      .where((e) => e.isolate.id == isolate.id)
+      .listen((e) { _isolate = e.isolate; _r.dirty(); });
     _r.enable();
-    _updatesSubscription = _updates
-      .where((M.IsolateUpdateEvent e) => e.isolate.id == isolate.id)
-      .listen((M.IsolateUpdateEvent e) { _isolate = e.isolate; _r.dirty(); });
   }
 
   @override