Add the MB config of the official win Clang bots.

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 692 matching lines @@
     },
 
     'official.desktop': {
       'mac64': 'gn_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': 'gn_official_x86',
       'win-asan': 'gn_official_syzyasan_x86',
+      'win-clang': 'gn_official_clang_x86',
       'win-pgo': [
         'gn_official_chrome_pgo_phase_1_x86',
         'gn_official_chrome_pgo_phase_2_x86',
       ],
       'win64': 'gn_official_x64',
+      'win64-clang': 'gn_official_clang_x64',
       'win64-pgo': [
         'gn_official_chrome_pgo_phase_1_x64',
         'gn_official_chrome_pgo_phase_2_x64',
       ],
     },
 
     'official.desktop.continuous': {
       'mac beta': 'gyp_official',
       'mac stable': 'gyp_official',
       'mac trunk': 'gn_official',
@@ skipping 502 matching lines @@
     ],
 
     'gn_linux_upload': [
       'gn_linux_upload', 'official', 'goma',
     ],
 
     'gn_official': [
       'gn', 'official',
     ],
 
+    'gn_official_clang_x64': [
+      'gn', 'clang', 'official', 'x64',
+    ],
+
+    'gn_official_clang_x86': [
+      'gn', 'clang', 'official', 'x86',
+    ],
+
     'gn_official_x86': [
       'gn', 'official', 'x86',
     ],
 
     'gn_official_goma': [
       'gn', 'official', 'goma',
     ],
 
     'gn_official_goma_lto': [
       'gn', 'official', 'goma', 'lto',
@@ skipping 1196 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',
     },
   },
 }