Track live instance and allocation counts for classes

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

Index: runtime/bin/vmservice/client/lib/src/observatory_elements/service_ref.dart
diff --git a/runtime/bin/vmservice/client/lib/src/observatory_elements/service_ref.dart b/runtime/bin/vmservice/client/lib/src/observatory_elements/service_ref.dart
index 55ab66423d9c46d81fffa35cd3ea91ff776b4ce4..a9cbe80288e7411ff7138f8107e09bbf6dd9db42 100644
--- a/runtime/bin/vmservice/client/lib/src/observatory_elements/service_ref.dart
+++ b/runtime/bin/vmservice/client/lib/src/observatory_elements/service_ref.dart
@@ -16,6 +16,7 @@ class ServiceRefElement extends ObservatoryElement {
   void refChanged(oldValue) {
     notifyPropertyChange(#url, "", url);
     notifyPropertyChange(#name, [], name);
+    notifyPropertyChange(#hoverText, "", hoverText);
   }
 
   String get url {
@@ -25,6 +26,15 @@ class ServiceRefElement extends ObservatoryElement {
     return '';
   }
 
+  String get hoverText {
+    if (ref == null) {
+      return '';
+    }
+    // Return the VM name by default.
+    var name = ref['name'];
+    return name != null ? name : '';
+  }
+
   String get name {
     if (ref == null) {
       return '';