Turn on hermetic toolchain for the FORCE_MAC_TOOLCHAIN fyi bot.

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 81 matching lines @@
       'CFI Linux CF': 'cfi_full_cfi_diag_release_static',
       'CFI Linux ToT': 'cfi_full_clang_tot_release_static',
       'CFI Linux': 'cfi_release_static',
       'CFI Linux Full': 'cfi_full_release_static',
       'Chromium Linux Goma Canary': 'release_bot',
       'Chromium Linux Goma Canary (clobber)': 'release_bot',
       'Chromium Linux Precise Goma LinkTest': 'release_bot',
       'Chromium Linux32 Goma Canary (clobber)': 'release_bot_x86',
       'Chromium Mac 10.10 MacViews': 'mac_views_browser_release_bot',
       'Chromium Mac 10.11': 'release_bot',
-      'Chromium Mac 10.11 Force Mac Toolchain': 'release_bot',
+      'Chromium Mac 10.11 Force Mac Toolchain': 'release_bot_mac_hermetic',
       'Chromium Mac 10.9 Goma Canary': 'release_bot',
       'Chromium Mac 10.9 Goma Canary (clobber)': 'release_bot',
       'Chromium Mac 10.9 Goma Canary (dbg)': 'debug_bot',
       'Chromium Mac 10.9 Goma Canary (dbg)(clobber)': 'debug_bot',
       'Chromium Win PGO Builder': {
         '1': 'official_optimize_chrome_pgo_phase_1_x86',
         '2': 'official_optimize_chrome_pgo_phase_2_x86',
       },
       'Chromium Win x64 PGO Builder': {
         '1': 'official_optimize_chrome_pgo_phase_1',
@@ skipping 351 matching lines @@
       'android_arm64_dbg_recipe': 'android_debug_trybot_arm64',
       'android_blink_rel': 'android_release_trybot',
       'android_clang_dbg_recipe': 'android_clang_asan_errorprone_findbugs_debug_trybot',
       'android_compile_dbg': 'android_debug_trybot',
       'android_compile_mips_dbg': 'android_debug_trybot_mipsel',
       'android_compile_rel': 'android_release_trybot',
       'android_compile_x64_dbg': 'android_debug_trybot_x64',
       'android_compile_x86_dbg': 'android_debug_trybot_x86',
       'android_coverage': 'android_debug_trybot_java_coverage',
       'android_cronet': 'android_cronet_release_trybot_arm_no_neon',
- 
+
       # TODO(crbug/597596): Switch this back to debug_trybot when cronet's
       # shared library loading is fixed.
       'android_cronet_tester': 'android_cronet_debug_static_bot_arm_no_neon',
 
       'android_n5x_swarming_rel': 'android_release_trybot_arm64',
       'android_optional_gpu_tests_rel': 'gpu_tests_deqp_android_release_trybot_arm64',
       'cast_shell_android': 'android_cast_debug_static_bot',
       'linux_android_dbg_ng': 'android_debug_trybot',
       'linux_android_rel_ng': 'android_release_trybot',
     },
@@ skipping 837 matching lines @@
     ],
 
     'release_bot_arm': [
       'release_bot', 'arm',
     ],
 
     'release_bot_chrome_with_codecs': [
       'release_bot', 'chrome_with_codecs',
     ],
 
+    'release_bot_mac_hermetic': [
+      'release_bot', 'mac_hermetic_toolchain',
+    ],
+
     'release_bot_mac_strip': [
       'release_bot', 'mac_strip',
     ],
 
     'release_bot_minimal_symbols': [
       'release_bot', 'minimal_symbols',
     ],
 
     'release_bot_x86': [
       'release_bot', 'x86',
@@ skipping 284 matching lines @@
     },
 
     'gpu_fyi_tests': {
       'mixins': ['gpu_tests', 'internal_gles2_conform_tests', 'angle_deqp_tests'],
     },
 
     'gpu_tests': {
       'mixins': ['chrome_with_codecs'],
     },
 
+    'mac_hermetic_toolchain': {
+      'gn_args': 'use_system_xcode=false',
+    },
+
     'hybrid': {
       'gn_args': 'v8_target_cpu="arm" target_cpu="x86"',
       'mixins': ['disable_nacl'],
     },
 
     'internal_gles2_conform_tests': {
       'gn_args': 'internal_gles2_conform_tests=true',
     },
 
     'java_coverage': {
@@ skipping 153 matching lines @@
       'gn_args': 'target_cpu="x86"',
     },
 
     'drfuzz': { 'gn_args': 'use_drfuzz=true' },
 
     'drmemory': {
       'gn_args': 'is_component_build=true enable_iterator_debugging=false',
     },
   },
 }