Add 'Sockets' to observatory.

runtime/bin/socket_patch.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 patch class RawServerSocket {
   /* patch */ static Future<RawServerSocket> bind(address,
                                                   int port,
                                                   {int backlog: 0,
                                                    bool v6Only: false}) {
     return _RawServerSocket.bind(address, port, backlog, v6Only);
@@ skipping 1043 matching lines @@
   void leaveMulticast(InternetAddress addr, NetworkInterface interface) {
     var interfaceAddr = multicastAddress(addr, interface);
     var interfaceIndex = interface == null ? 0 : interface.index;
     var result = nativeLeaveMulticast(
         addr._in_addr,
         interfaceAddr == null ? null : interfaceAddr._in_addr,
         interfaceIndex);
     if (result is OSError) throw result;
   }
 
-  String get _serviceTypePath => 'io/socket';
+  String get _serviceTypePath => 'io/sockets';
   String get _serviceTypeName => 'Socket';
 
   Map _toJSON(bool ref) {
+    var name = '${address.host}:$port';
+    if (isTcp && !isListening) name += " <-> ${remoteAddress.host}:$remotePort";
     var r = {
       'id': _servicePath,
       'type': _serviceType(ref),
-      'name': '${address.host}:$port',
-      'user_name': '${address.host}:$port',
+      'name': name,
+      'user_name': name,
     };
     if (ref) {
       return r;
     }
     r['port'] = port;
     r['address'] = address.host;
+    r['fd'] = nativeGetSocketId();
     return r;
   }
 
   void nativeSetSocketId(int id) native "Socket_SetSocketId";
   nativeAvailable() native "Socket_Available";
   nativeRead(int len) native "Socket_Read";
   nativeRecvFrom() native "Socket_RecvFrom";
   nativeWrite(List<int> buffer, int offset, int bytes)
       native "Socket_WriteList";
   nativeSendTo(List<int> buffer, int offset, int bytes,
@@ skipping 800 matching lines @@
                        String address,
                        List<int> in_addr,
                        int port) {
   return new Datagram(
       data,
       new _InternetAddress(address, null, in_addr),
       port);
 }
 
 String _socketsStats() => _SocketsObservatory.toJSON();