Add mb config for linux_chromium_headless_rel

tools/mb/mb_config.pyl

 # Copyright 2015 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.
 
 {
   # This is a map of buildbot master names -> buildbot builder names ->
   # config names (where each config name is a key in the 'configs' dict,
   # below). MB uses this dict to look up which config to use for a given bot.
   'masters': {
     'chromeos.chrome': {
@@ skipping 509 matching lines @@
       'linux_chromium_chromeos_msan_rel_ng': 'chromeos_msan_release_bot',
       'linux_chromium_chromeos_ozone_rel_ng': 'chromeos_with_codecs_ozone_release_trybot',
       'linux_chromium_chromeos_rel_ng': 'chromeos_with_codecs_release_trybot',
       'linux_chromium_clobber_rel_ng': 'release_trybot',
       'linux_chromium_compile_dbg_32_ng': 'debug_trybot_x86',
       'linux_chromium_compile_dbg_ng': 'debug_trybot',
       'linux_chromium_compile_rel_ng': 'release_trybot',
       'linux_chromium_dbg_32_ng': 'debug_trybot_x86',
       'linux_chromium_dbg_ng': 'debug_trybot',
       'linux_chromium_gn_upload': 'gn_linux_upload',
-      'linux_chromium_headless_dbg': '//build/args/bots/tryserver.chromium.linux/headless_linux_dbg_trybot.gn',
+      'linux_chromium_headless_dbg': '//build/args/bots/tryserver.chromium.linux/linux_chromium_headless_dbg.gn',
+      'linux_chromium_headless_rel': '//build/args/bots/tryserver.chromium.linux/linux_chromium_headless_rel.gn',
 
       # This is intentionally a release_bot and not a release_trybot;
       # enabling DCHECKs seems to cause flaky failures that don't show up
       # on the continuous builder.
       'linux_chromium_msan_rel_ng': 'msan_release_bot',
 
       'linux_chromium_rel_ng': 'gpu_tests_release_trybot',
       'linux_chromium_tsan_rel_ng': 'tsan_disable_nacl_release_trybot',
 
       # This is 'release_bot' rather than 'release_trybot' because
@@ skipping 1269 matching lines @@
       'gn_args': 'target_cpu="x86"',
     },
 
     'drfuzz': { 'gn_args': 'use_drfuzz=true' },
 
     'drmemory': {
       'gn_args': 'is_component_build=true enable_iterator_debugging=false',
     },
   },
 }