Adding Trybots for Mac 10.11 to tryserver.chromium.mac for Findit use

masters/master.tryserver.chromium.mac/slaves.cfg

 # -*- python -*-
 # ex: set syntax=python:
 # Copyright 2014 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.
 
 # See master.experimental/slaves.cfg for documentation.
 
 def mac():
   cq_slaves = (
@@ skipping 36 matching lines @@
       'mac_chromium_variable_10.10',
       'mac_chromium_variable_10.10_layout',
       'mac_chromium_archive_rel_ng',
       'mac_chromium_asan_rel_ng',
       'mac_chromium_asan_variable',
       'mac_chromium_variable_chrome',
       'mac_chromium_variable_gn',
       'mac_chromium_variable_layout',
   ]
 
+  # Mac 10.11.
+  optional4_slaves = ['build417-m4']
+  optional4_builders = [
+      'mac_chromium_variable_10.11',
+      'mac_chromium_variable_10.11_layout',
+  ]
+
   out = []
   out.extend(
     {
       'master': 'TryServerChromiumMac',
       'builder': cq_builders,
       'preferred_builder': cq_builders[i % len(cq_builders)],
       'hostname': slave,
       'os': 'mac',
       'version': '10.9',
       'bits': '64',
@@ skipping 60 matching lines @@
     {
       'master': 'TryServerChromiumMac',
       'builder': optional3_builders,
       'hostname': slave,
       'os': 'mac',
       'version': '10.10',
       'bits': '64',
       'pool': 'mac_optional_10_10',
     } for slave in optional3_slaves
   )
+  out.extend(
+    {
+      'master': 'TryServerChromiumMac',
+      'builder': optional4_builders,
+      'hostname': slave,
+      'os': 'mac',
+      'version': '10.11',
+      'bits': '64',
+      'pool': 'mac_optional_10_11',
+    } for slave in optional4_slaves
+  )
 
   return out
 
 
 def ios():
   # Split by simulator/device because it splits the load evenly.
   cq_builders_dbg = [
     'ios-simulator',
     'ios-simulator-gn',
   ]
@@ skipping 38 matching lines @@
       'pool': 'ios_cq_rel',
     } for slave in cq_slaves_rel]
 
   # TODO(lliabraa): Add test_slaves once we're actually running iOS tests on
   # the bots.
 
   return compile_slaves_dbg + compile_slaves_rel
 
 
 slaves = mac() + ios()