Supporting both FieldRef and InstanceRef in RetainingPathItem.parentField

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

Index: runtime/observatory/lib/src/elements/retaining_path.dart
diff --git a/runtime/observatory/lib/src/elements/retaining_path.dart b/runtime/observatory/lib/src/elements/retaining_path.dart
index 40f77e8cc5878ba027f7bfa8f43145dc2c81f789..b0f2ea026179d420c6ee20be3074304ca9596051 100644
--- a/runtime/observatory/lib/src/elements/retaining_path.dart
+++ b/runtime/observatory/lib/src/elements/retaining_path.dart
@@ -99,11 +99,10 @@ class RetainingPathElement extends HtmlElement implements Renderable {
 
     if (item.parentField != null) {
       content.add(
-        new DivElement()
+        new SpanElement()
           ..children = [
               new SpanElement()..text = 'from ',
-                new InstanceRefElement(_isolate, item.parentField, _instances,
-                                       queue: _r.queue),
+              anyRef(_isolate, item.parentField, _instances, queue: _r.queue),
               new SpanElement()..text = ' of ',
           ]);
     } else if (item.parentListIndex != null) {