Add 'Sockets' to observatory.

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

Index: runtime/bin/vmservice/client/lib/src/elements/service_view.dart
diff --git a/runtime/bin/vmservice/client/lib/src/elements/service_view.dart b/runtime/bin/vmservice/client/lib/src/elements/service_view.dart
index 5a0261bc6f840ff162ba8895aa2770162c0deb2a..3109f006307aaaacab177ebebef77824aa06742d 100644
--- a/runtime/bin/vmservice/client/lib/src/elements/service_view.dart
+++ b/runtime/bin/vmservice/client/lib/src/elements/service_view.dart
@@ -101,6 +101,11 @@ class ServiceObjectViewElement extends ObservatoryElement {
             new Element.tag('io-http-server-view');
         element.httpServer = object;
         return element;
+      case 'SocketList':
+        IOSocketListViewElement element =
+            new Element.tag('io-socket-list-view');
+        element.list = object;
+        return element;
       case 'Socket':
         IOSocketViewElement element = new Element.tag('io-socket-view');
         element.socket = object;