Adding variable builder corresponding to Cast Linux

masters/master.tryserver.chromium.linux/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 linux():
   chromeos_boards = ('x86-generic', 'amd64-generic', 'daisy')
@@ skipping 26 matching lines @@
     'Chromium Linux Codesearch Builder',
     'ChromiumOS Codesearch Builder',
   ]
   optional_builders += [
     'chromeos_%s_variable' % (board,)
     for board in chromeos_boards
   ]
   optional_builders += [
     'linux_arm',
     'linux_chromium_asan_variable',
+    'linux_chromium_cast_variable',
     'linux_chromium_chromeos_asan_variable',
     'linux_chromium_chromeos_compile_rel_ng',
     'linux_chromium_chromeos_dbg_ng',
     'linux_chromium_chromeos_msan_rel_ng',
     'linux_chromium_chromeos_variable',
     'linux_chromium_clang_upload',
     'linux_chromium_compile_rel_ng',
     'linux_chromium_dbg_ng',
     'linux_chromium_gn_chromeos_variable',
     'linux_chromium_gn_upload',
@@ skipping 86 matching lines @@
       'builder': ['linux_chromium_browser_side_navigation_rel'],
       'hostname': 'slave914-c4',
       'pool': 'linux_chromium_browser_side_navigation_rel',
     }
   ])
 
   return result
 
 
 slaves = linux()