Flip 'Google Chrome Mac' builder on chromium.chrome back to GYP.

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': {
     # Take care when changing any of these builders to ensure that you do not
@@ skipping 45 matching lines @@
       'Lollipop Low-end Tester': 'android_gn_debug_static_bot',
       'Lollipop Phone Tester': 'android_gn_debug_static_bot',
       'Lollipop Tablet Tester': 'android_gn_debug_static_bot',
       'Marshmallow 64 bit Tester': 'android_gn_debug_static_bot_arm64',
       'Marshmallow Tablet Tester': 'android_gn_debug_static_bot',
     },
 
     'chromium.chrome': {
       'Google Chrome ChromeOS': 'gn_official_goma_chromeos',
       'Google Chrome Linux x64': 'gn_official_goma',
-      'Google Chrome Mac': 'gn_official_goma',
+      'Google Chrome Mac': 'gyp_official_goma',
       'Google Chrome Win': 'gn_official_goma_minimal_symbols_x86',
     },
 
     'chromium.chromiumos': {
       'ChromiumOS amd64-generic Compile': 'cros_chrome_sdk_gn',
       'ChromiumOS daisy Compile': 'cros_chrome_sdk_gn',
       'ChromiumOS x86-generic Compile': 'cros_chrome_sdk_gn',
       'Linux ChromiumOS Builder': 'swarming_chromeos_gn_release_bot',
       'Linux ChromiumOS Builder (dbg)': 'swarming_chromeos_gn_debug_bot',
       'Linux ChromiumOS Full': 'swarming_chromeos_gn_release_bot',
@@ skipping 2222 matching lines @@
     },
 
     'drfuzz': { 'gn_args': 'use_drfuzz=true' },
 
     'drmemory': {
       'gn_args': 'is_component_build=true enable_iterator_debugging=false',
       'gyp_defines': 'component=shared_library build_for_tool=drmemory',
     },
   },
 }