[mb] Use optimize_for_fuzzing for libfuzzer 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 1312 matching lines @@
 
     'release_drmemory_drfuzz': [
       'release', 'drmemory', 'drfuzz', 'chrome_with_codecs',
     ],
 
     'release_drmemory_drfuzz_x86': [
       'release', 'drmemory', 'drfuzz', 'x86', 'chrome_with_codecs',
      ],
 
     'release_libfuzzer_asan': [
-      'release', 'libfuzzer', 'asan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
+      'release', 'libfuzzer', 'asan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing',
     ],
 
     'release_libfuzzer_asan_clang_tot': [
       'clang_tot', 'release', 'libfuzzer', 'asan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
     ],
 
     'release_libfuzzer_mac_asan': [
-      'release', 'libfuzzer', 'asan', 'chrome_with_codecs', 'pdf_xfa', 'disable_nacl',
+      'release', 'libfuzzer', 'asan', 'chrome_with_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing',
     ],
 
     'release_libfuzzer_msan': [
-      'release', 'libfuzzer', 'msan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
+      'release', 'libfuzzer', 'msan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing',
     ],
 
     'release_libfuzzer_ubsan': [
-      'release', 'libfuzzer', 'ubsan_security', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
+      'release', 'libfuzzer', 'ubsan_security', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing',
     ],
 
     'release_trybot': [
       'release_trybot',
     ],
 
     'release_trybot_arm': [
       'release_trybot', 'arm',
     ],
 
@@ skipping 310 matching lines @@
 
     'official': {
       'mixins': ['official_optimize'],
       'gn_args': 'is_chrome_branded=true',
     },
 
     'official_optimize': {
       'gn_args': 'is_official_build=true is_debug=false',
     },
 
+    'optimize_for_fuzzing': {
+      'gn_args': 'optimize_for_fuzzing=true',
+    },
+
     'ozone': {
       'gn_args': 'use_ozone=true',
     },
 
     'pdf_xfa': {
       'gn_args': 'pdf_enable_xfa=true',
     },
 
     # Note: This is probably not what you want to use. Instead use one of the
     # chrome_with_codecs or chromeos_with_codecs mixins.
@@ skipping 85 matching lines @@
       'gn_args': 'target_cpu="x86"',
     },
 
     'drfuzz': { 'gn_args': 'use_drfuzz=true' },
 
     'drmemory': {
       'gn_args': 'is_component_build=true enable_iterator_debugging=false',
     },
   },
 }