Adds clearer function to create rtc::Thread without Physical SocketServer

webrtc/base/base.gyp

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 {
   'includes': [ '../build/common.gypi', ],
@@ skipping 223 matching lines @@
         'messagehandler.cc',
         'messagehandler.h',
         'messagequeue.cc',
         'messagequeue.h',
         'nethelpers.cc',
         'nethelpers.h',
         'network.cc',
         'network.h',
         'networkmonitor.cc',
         'networkmonitor.h',
+        'nullsocketserver.cc',
         'nullsocketserver.h',
         'openssl.h',
         'openssladapter.cc',
         'openssladapter.h',
         'openssldigest.cc',
         'openssldigest.h',
         'opensslidentity.cc',
         'opensslidentity.h',
         'opensslstreamadapter.cc',
         'opensslstreamadapter.h',
@@ skipping 386 matching lines @@
     },
     {
      'target_name': 'gtest_prod',
       'type': 'static_library',
       'sources': [
         'gtest_prod_util.h',
       ],
     },
   ],
 }