Enable UMA histogram logger for low memor kill events in ArcMetricsService.

chrome/chrome_browser_chromeos.gypi

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     # These files lists are shared with the GN build.
     'browser_chromeos_sources': [
         # All .cc, .h, .m, and .mm files under browser/chromeos, except for tests
@@ skipping 51 matching lines @@
         'browser/chromeos/arc/arc_intent_helper_bridge.h',
         'browser/chromeos/arc/arc_service_launcher.cc',
         'browser/chromeos/arc/arc_service_launcher.h',
         'browser/chromeos/arc/arc_policy_bridge.cc',
         'browser/chromeos/arc/arc_policy_bridge.h',
         'browser/chromeos/arc/arc_process.h',
         'browser/chromeos/arc/arc_process_service.cc',
         'browser/chromeos/arc/arc_process_service.h',
         'browser/chromeos/arc/settings_bridge.cc',
         'browser/chromeos/arc/settings_bridge.h',
-        'browser/chromeos/arc/arc_low_memory_killer_monitor.h',
-        'browser/chromeos/arc/arc_low_memory_killer_monitor.cc',
         'browser/chromeos/arc/arc_optin_uma.cc',
         'browser/chromeos/arc/arc_optin_uma.h',
         'browser/chromeos/attestation/attestation_ca_client.cc',
         'browser/chromeos/attestation/attestation_ca_client.h',
         'browser/chromeos/attestation/attestation_policy_observer.cc',
         'browser/chromeos/attestation/attestation_policy_observer.h',
         'browser/chromeos/attestation/platform_verification_dialog.cc',
         'browser/chromeos/attestation/platform_verification_dialog.h',
         'browser/chromeos/attestation/platform_verification_flow.cc',
         'browser/chromeos/attestation/platform_verification_flow.h',
@@ skipping 1254 matching lines @@
         'browser/chromeos/attestation/attestation_signed_data.proto',
       ],
       'variables': {
         'proto_in_dir': 'browser/chromeos/attestation',
         'proto_out_dir': 'chrome/browser/chromeos/attestation',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }