Added comments explaining why some code is not used / returns empty results as a result of issue #2…

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

Index: runtime/observatory/lib/src/elements/isolate_view.dart
diff --git a/runtime/observatory/lib/src/elements/isolate_view.dart b/runtime/observatory/lib/src/elements/isolate_view.dart
index 7e7599e58744b5e9bf7e3b1545ded14d781faecf..8c0f186831c109159d5ed67a7d28cf9be26a6f16 100644
--- a/runtime/observatory/lib/src/elements/isolate_view.dart
+++ b/runtime/observatory/lib/src/elements/isolate_view.dart
@@ -389,6 +389,8 @@ class IsolateViewElement extends HtmlElement implements Renderable {
                     ..children = [
                       new SpanElement()
                         ..children = [
+                          // TODO(bkonyi): zones will always be empty. See
+                          // issue #28885.
                           new SpanElement()
                             ..text = 'zone ${index++} ',
                           new CurlyBlockElement(queue: _r.queue)