Flip Mac official builders 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 597 matching lines @@
       'Win7 (32) Tests': 'none',
       'Win7 Tests (1)': 'none',
       'Win7 Tests (dbg)(1)': 'none',
       'Win8 GYP': 'swarming_gyp_release_bot_minimal_symbols_x86',
       'Win8 GYP (dbg)': 'swarming_gyp_debug_bot_minimal_symbols_x86',
       'WinClang64 (dbg)': 'win_clang_debug_bot',
     },
 
     'official.desktop': {
       'blimp-engine': '//build/args/bots/official.desktop/blimp-engine.gn',
-      'mac64': 'gn_official',
+      'mac64': 'gyp_official',
       'precise64': 'gn_official',
 
       # Currently the official bots set mini_installer_official_deps=1
       # but it's not clear if that's actually used anywhere.
       'win': 'gyp_official',
       'win-asan': 'gyp_official_syzyasan',
       'win-pgo': 'gyp_official_winpgo',
       'win64': 'gyp_official_x64',
       'win64-pgo': 'gyp_official_winpgo_x64',
     },
 
     'official.desktop.continuous': {
       'mac beta': 'gyp_official',
       'mac stable': 'gyp_official',
-      'mac trunk': 'gn_official',
+      'mac trunk': 'gyp_official',
       'precise64 beta': 'gn_official',
       'precise64 stable': 'gn_official',
       'precise64 trunk': 'gn_official',
       'win beta': 'gyp_official_six_concurrent_links',
       'win stable': 'gyp_official_six_concurrent_links',
       'win trunk': 'gyp_official_six_concurrent_links',
       'win64 trunk': 'gyp_official_x64_six_concurrent_links',
     },
 
     'tryserver.blink': {
@@ skipping 1660 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',
     },
   },
 }