Improved how closures are displayed by <instance-ref>.

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

Index: runtime/bin/vmservice/client/lib/src/observatory_elements/observatory_element.dart
diff --git a/runtime/bin/vmservice/client/lib/src/observatory_elements/observatory_element.dart b/runtime/bin/vmservice/client/lib/src/observatory_elements/observatory_element.dart
index acd06464d0594a6a85dd259efa07e71f8f52cfcb..74db7e08333c118f3fa105a881ef948f9c579163 100644
--- a/runtime/bin/vmservice/client/lib/src/observatory_elements/observatory_element.dart
+++ b/runtime/bin/vmservice/client/lib/src/observatory_elements/observatory_element.dart
@@ -117,6 +117,10 @@ class ObservatoryElement extends PolymerElement {
     return type == '@Instance';
   }
 
+  bool isClosureRef(String type) {
+    return type == '@Closure';
+  }
+
   bool isListRef(String type) {
     return (type == '@GrowableObjectArray' ||
             type == '@Array');
@@ -129,8 +133,9 @@ class ObservatoryElement extends PolymerElement {
               '@Biginit',
               '@Bool',
               '@String',
+              '@Closure',
               '@Instance',
-              '@GrowableObjectArray'
+              '@GrowableObjectArray',
               '@Array'].contains(type));
   }
 }