WebRTC: Add Libfuzzer commit and trybot.

masters/master.client.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 32-bit.
   {
     'master': 'WebRTC',
     'os': 'linux',
     'version': 'precise',
@@ skipping 18 matching lines @@
       'Android32 Clang (dbg)',
       'Android64 Builder',
       'Android64 Builder (dbg)',
       'Android64 Builder x64 (dbg)',
       'Android32 GN',
       'Android32 GN (dbg)',
       'Linux64 Debug',
       'Linux64 Release',
       'Linux64 Debug (GN)',
       'Linux64 Release (GN)',
+      'Linux64 Release (Libfuzzer)',
       'Linux Asan',
       'Linux MSan',
       'Linux Tsan v2',
     ],
     'hostname': host,
   } for host in list('vm%d-m3' % i for i in range(305, 309) + [4, 201, 203]) +
                 list('slave%d-c3' % i for i in range(6, 10))
 ] + [
   {
     'master': 'WebRTC',
@@ skipping 154 matching lines @@
     'master': 'WebRTC',
     'os': 'win',
     'version': 'win7',
     'bits': '64',
     'builder': [
       'Win32 Release [large tests]',
     ],
     'hostname': 'chromeperf90',
   }
 ]