Add Socket ref to HttpServer.

sdk/lib/io/http_impl.dart

Index: sdk/lib/io/http_impl.dart
diff --git a/sdk/lib/io/http_impl.dart b/sdk/lib/io/http_impl.dart
index e9b610e00fedc9aa32c6c885e65b1935b9dc5e3f..ab850f0446d999a79697e102407a61b7a880f922 100644
--- a/sdk/lib/io/http_impl.dart
+++ b/sdk/lib/io/http_impl.dart
@@ -2041,9 +2041,6 @@ class _HttpServer
   // Use default Map so we keep order.
   static Map<int, _HttpServer> _servers = new Map<int, _HttpServer>();
 
-  final String _serviceTypePath = 'io/http/servers';
-  final String _serviceTypeName = 'HttpServer';
-
   String serverHeader;
 
   Duration _idleTimeout;
@@ -2226,6 +2223,9 @@ class _HttpServer
     return result;
   }
 
+  String get _serviceTypePath => 'io/http/servers';
+  String get _serviceTypeName => 'HttpServer';
+
   Map _toJSON(bool ref) {
     var r = {
       'id': _servicePath,
@@ -2236,6 +2236,16 @@ class _HttpServer
     if (ref) {
       return r;
     }
+    try {
+      r['socket'] = _serverSocket._toJSON(true);
+    } catch (_) {
+      r['socket'] = {
+        'id': _servicePath,
+        'type': '@Socket',
+        'name': 'UserSocket',
+        'user_name': 'UserSocket',
+      };
+    }
     r['port'] = port;
     r['address'] = address.host;
     r['active'] = _activeConnections.length;