Introduce Instance.kind.

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

Index: runtime/observatory/lib/src/elements/service_ref.dart
diff --git a/runtime/observatory/lib/src/elements/service_ref.dart b/runtime/observatory/lib/src/elements/service_ref.dart
index e238141b0d739e101b32c68edeedf45ddecc3a31..ba00201775696e768b429bbe77c8efbd6b8b25fe 100644
--- a/runtime/observatory/lib/src/elements/service_ref.dart
+++ b/runtime/observatory/lib/src/elements/service_ref.dart
@@ -102,17 +102,15 @@ class AnyServiceRefElement extends ObservatoryElement {
         ServiceRefElement element = new Element.tag('script-ref');
         element.ref = ref;
         return element;
+      case 'Instance':
+      case 'Sentinel':
+        ServiceRefElement element = new Element.tag('instance-ref');
+        element.ref = ref;
+        return element;
       default:
-        if (ref.isInstance ||
-            ref.isSentinel) {  // TODO(rmacnak): Separate this out.
-          ServiceRefElement element = new Element.tag('instance-ref');
-          element.ref = ref;
-          return element;
-        } else {
-          SpanElement element = new Element.tag('span');
-          element.text = "<<Unknown service ref: $ref>>";
-          return element;
-        }
+        SpanElement element = new Element.tag('span');
+        element.text = "<<Unknown service ref: $ref>>";
+        return element;
     }
   }