Update navigator.services API to use the new services.onconnect event [2/3].

content/common/service_port_service.mojom

 // Copyright 2015 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.
 
 module content;
 
 enum ServicePortConnectResult {
   ACCEPT,
   REJECT
 };
@@ skipping 12 matching lines @@
   PostMessage(int32 port_id, string message,
               array<MojoTransferredMessagePort> ports);
   ClosePort(int32 port_id);
 };
 
 interface ServicePortServiceClient {
   PostMessage(int32 port_id, string message,
               array<MojoTransferredMessagePort> ports,
               array<int32> new_routing_ids);
 };
+
+interface ServicePortDispatcher {
+  Connect(string target_url, string origin, int32 port_id)
+      => (ServicePortConnectResult result, string name, string data);
+};