Add basic TCP socket mojo implementation

mojo/services/public/interfaces/network/network_service.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import "mojo/services/public/interfaces/network/cookie_store.mojom"
 import "mojo/services/public/interfaces/network/net_address.mojom"
 import "mojo/services/public/interfaces/network/network_error.mojom"
 import "mojo/services/public/interfaces/network/tcp_bound_socket.mojom"
 import "mojo/services/public/interfaces/network/tcp_connected_socket.mojom"
 import "mojo/services/public/interfaces/network/udp_socket.mojom"
@@ skipping 27 matching lines @@
   CreateTCPBoundSocket(NetAddress? local_address,
                        TCPBoundSocket& bound_socket)
       => (NetworkError result, NetAddress? bound_to);
 
   // Creates a client socket connected to the given remote address. A local
   // address and port will be allocated for the connection and passed to the
   // callback on success.
   //
   // If you want control over the local address and port, instead use
   // CreateTCPBoundSocket.
+  //
+  // IMPORTANT: This does not work yet! We need to add a new parameter to
+  // indicate the protocol type (IPv4 or IPv6) actually be able to create the
+  // right type of socket. We also need to figure out how the client is supposed
+  // to decide between IPv4 and IPv6 on a given system.
   CreateTCPConnectedSocket(NetAddress remote_address,
                            handle<data_pipe_consumer> send_stream,
                            handle<data_pipe_producer> receive_stream,
                            TCPConnectedSocket& client_socket)
       => (NetworkError result,
           NetAddress? local_address);
 
   CreateUDPSocket(UDPSocket& socket);
 };
 
 }