WebRTC: Add trybot for iOS SDK Framework build.

masters/master.tryserver.webrtc/slaves.cfg

 # Copyright (c) 2012 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.
 
 slaves = [
   # Linux.
   {
     'master': 'WebRTCTryServer',
     'os': 'linux',
     'version': 'trusty',
@@ skipping 96 matching lines @@
       'mac_compile_rel',
       'mac_dbg',
       'mac_rel',
       'mac_swarming',
       'mac_gn_dbg',
       'mac_gn_rel',
       'ios_dbg',
       'ios_rel',
       'ios_arm64_dbg',
       'ios_arm64_rel',
+      'ios_api_framework',
       'ios32_sim_dbg',
       'ios64_sim_dbg',
       'ios64_gn_dbg',
       'ios64_gn_rel',
     ],
     'hostname': 'vm%d-m4' % i,
   } for i in range(510, 513) + range(665, 667) + range(738, 741) +
              range(818, 820) + [748, 1033]
 ] + [
   # Mac bare-metal machines with audio devices and headsets.
@@ skipping 42 matching lines @@
     'master': 'WebRTCTryServer',
     'os': 'win',
     'version': 'win7',
     'bits': '64',
     'builder': [
       'win_baremetal',
     ],
     'hostname': hostname,
   } for hostname in ['build23-a4', 'build139-b4']
 ]