2nd attempt at adding streamListen/streamCancel to the service protocol.

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 ba00201775696e768b429bbe77c8efbd6b8b25fe..7c5ff020ac3e430b4a69908a185b2ecc1818e652 100644
--- a/runtime/observatory/lib/src/elements/service_ref.dart
+++ b/runtime/observatory/lib/src/elements/service_ref.dart
@@ -121,7 +121,7 @@ class AnyServiceRefElement extends ObservatoryElement {
       Logger.root.info('Viewing null object.');
       return;
     }
-    var type = ref.vmType;
+    var type = ref.type;
     var element = _constructElementForRef();
     if (element == null) {
       Logger.root.info('Unable to find a ref element for \'${type}\'');