Update macOS FYI toolchain bot to compile with 10.12 SDK.

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 .pyl, or "Python Literal", file. You can treat it just like a
 # .json file, with the following exceptions:
 # * all keys must be quoted (use single quotes, please);
 # * comments are allowed, using '#' syntax; and
 # * trailing commas are allowed.
 
@@ skipping 96 matching lines @@
       'CFI Linux Full': 'cfi_full_cfi_diag_thin_lto_release_static_dcheck_always_on_goma',
       'CFI ThinLTO Linux ToT': 'cfi_thin_lto_clang_tot_full_symbols_release_static_use_lld',
       'Chromium Linux Goma Canary': 'release_bot',
       'Chromium Linux Goma Canary': 'release_bot',
       'Chromium Linux Goma Canary (clobber)': 'release_bot',
       'Chromium Linux Goma Canary LocalOutputCache': '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_mac_hermetic',
+      'Chromium Mac 10.11 Force Mac Toolchain': 'release_bot_mac_new_sdk',
       '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 Mac Goma Canary LocalOutputCache': 'release_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': {
@@ skipping 1297 matching lines @@
     ],
 
     'release_bot_arm64': [
       'release_bot', 'arm64',
     ],
 
     'release_bot_chrome_with_codecs': [
       'release_bot', 'chrome_with_codecs',
     ],
 
-    'release_bot_mac_hermetic': [
-      'release_bot', 'mac_hermetic_toolchain',
+    'release_bot_mac_new_sdk': [
+      'release_bot', 'mac_new_sdk',
     ],
 
     'release_bot_mac_strip': [
       'release_bot', 'mac_strip',
     ],
 
     'release_bot_x86': [
       'release_bot', 'x86',
     ],
 
@@ skipping 321 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',
+    'mac_new_sdk': {
+      'gn_args': 'mac_sdk_min=10.12',
     },
 
     'headless': {
       'args_file': '//build/args/headless.gn',
     },
 
     'hybrid': {
       'gn_args': 'v8_target_cpu="arm" target_cpu="x86"',
       'mixins': ['disable_nacl'],
     },
@@ skipping 182 matching lines @@
 
     'x64': {
       'gn_args': 'target_cpu="x64"',
     },
 
     'x86': {
       'gn_args': 'target_cpu="x86"',
     },
   },
 }