Move URL Loader creation to a separate factory object.

mojo/mojo_services.gyp

 # 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.
 
 {
   'targets': [{
     'target_name': 'network_service_bindings_mojom',
     'type': 'none',
     'variables': {
       'mojom_files': [
         'services/network/public/interfaces/cookie_store.mojom',
         'services/network/public/interfaces/http_connection.mojom',
         'services/network/public/interfaces/http_message.mojom',
         'services/network/public/interfaces/http_server.mojom',
         'services/network/public/interfaces/net_address.mojom',
         'services/network/public/interfaces/network_error.mojom',
         'services/network/public/interfaces/network_service.mojom',
         'services/network/public/interfaces/tcp_bound_socket.mojom',
         'services/network/public/interfaces/tcp_connected_socket.mojom',
         'services/network/public/interfaces/tcp_server_socket.mojom',
         'services/network/public/interfaces/udp_socket.mojom',
         'services/network/public/interfaces/url_loader.mojom',
+        'services/network/public/interfaces/url_loader_factory.mojom',
         'services/network/public/interfaces/web_socket.mojom',
       ],
       'mojom_include_path': '<(DEPTH)/mojo/services',
     },
     'includes': [
       '../third_party/mojo/mojom_bindings_generator_explicit.gypi',
     ],
   }, {
     # GN version: //mojo/services/network/public/interfaces
     'target_name': 'network_service_bindings_lib',
     'type': 'static_library',
     'dependencies': [
       'network_service_bindings_mojom',
     ],
   }, {
     # Target used to depend only on the bindings generation action, not on any
     # outputs.
     'target_name': 'network_service_bindings_generation',
     'type': 'none',
     'hard_dependency': 1,
     'dependencies': [
       'network_service_bindings_mojom',
     ],
   }],
 }