Use GUID instead of servicePath in network settings

extensions/common/api/networking_private.json

 // Copyright (c) 2013 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.
 
 [
   {
     "namespace":"networkingPrivate",
     "description": "none",
     "compiler_options": {
       "implemented_in": "extensions/browser/api/networking_private/networking_private_api.h"
@@ skipping 137 matching lines @@
             "type": "string",
             "description": "The unique identifier of the network to set properties on."
           },
           {
             "name": "properties",
             "$ref": "NetworkProperties",
             "description": "The properties to set on the network."
           },
           {
             "name": "callback",
+            "optional": true,
             "type": "function",
             "parameters": []
           }
         ]
       },
       {
         "name": "createNetwork",
         "description": "Creates a new network configuration from properties. If a matching configured network already exists, this will fail. Otherwise returns the guid of the new network.",
         "parameters": [
           {
             "name": "shared",
             "type": "boolean",
             "description": "If true, share this network configuration with other users."
           },
           {
             "name": "properties",
             "$ref": "NetworkProperties",
             "description": "The properties to configure the new network with."
           },
           {
             "name": "callback",
+            "optional": true,
             "type": "function",
             "parameters": [
               {
                 "name": "networkGuid",
                 "type": "string"
               }
             ]
           }
         ]
       },
@@ skipping 228 matching lines @@
             "type": "string",
             "description": "The IP or MAC address of the peer with which to enable a TDLS connection."
           },
           {
             "name": "enabled",
             "type": "boolean",
             "description": "If true, enable TDLS, otherwise disable TDLS."
           },
           {
             "name": "callback",
+            "optional": true,
             "type": "function",
             "parameters": [
               {
                 "name": "status",
                 "type": "string"
               }
             ],
             "description": "A callback function that receives a string with an error or the current TDLS status. 'Failed' indicates that the request failed (e.g. MAC address lookup failed). 'Timeout' indicates that the lookup timed out. Otherwise a valid status is returned (see getWifiTDLSStatus)."
           }
         ]
@@ skipping 79 matching lines @@
           },
           {
             "name": "status",
             "$ref": "CaptivePortalStatus"
           }
         ]
       }
     ]
   }
 ]