Various vmservice/observatory fixes:

runtime/bin/vmservice/client/lib/src/elements/service_ref.dart

Index: runtime/bin/vmservice/client/lib/src/elements/service_ref.dart
diff --git a/runtime/bin/vmservice/client/lib/src/elements/service_ref.dart b/runtime/bin/vmservice/client/lib/src/elements/service_ref.dart
index 9af8c163b566a4836fd2c7f887c74b606191a200..2286b1a625557f32b3210abadafce5d19e91ccaa 100644
--- a/runtime/bin/vmservice/client/lib/src/elements/service_ref.dart
+++ b/runtime/bin/vmservice/client/lib/src/elements/service_ref.dart
@@ -17,6 +17,7 @@ class ServiceRefElement extends ObservatoryElement {
   void refChanged(oldValue) {
     notifyPropertyChange(#url, "", url);
     notifyPropertyChange(#name, [], name);
+    notifyPropertyChange(#nameIsEmpty, 0, 1);
     notifyPropertyChange(#hoverText, "", hoverText);
   }
 
@@ -47,4 +48,9 @@ class ServiceRefElement extends ObservatoryElement {
     }
     return ref.name;
   }
+
+  // Workaround isEmpty not being useable due to missing @MirrorsUsed.
+  bool get nameIsEmpty {
+    return name.isEmpty;
+  }
 }