Track thread activities in order to diagnose hangs.

base/base.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.
 
 {
   'includes': [
     'trace_event/trace_event.gypi',
   ],
   'target_defaults': {
     'variables': {
@@ skipping 376 matching lines @@
           'message_loop/message_loop_task_runner.h',
           'message_loop/message_pump.cc',
           'message_loop/message_pump.h',
           'message_loop/message_pump_android.cc',
           'message_loop/message_pump_android.h',
           'message_loop/message_pump_default.cc',
           'message_loop/message_pump_default.h',
           'message_loop/message_pump_win.cc',
           'message_loop/message_pump_win.h',
           'message_loop/timer_slack.h',
+          'metrics/activity_tracker.cc',
+          'metrics/activity_tracker.h',
           'metrics/bucket_ranges.cc',
           'metrics/bucket_ranges.h',
           'metrics/histogram.cc',
           'metrics/histogram.h',
           'metrics/histogram_base.cc',
           'metrics/histogram_base.h',
           'metrics/histogram_delta_serialization.cc',
           'metrics/histogram_delta_serialization.h',
           'metrics/histogram_flattener.h',
           'metrics/histogram_macros.h',
@@ skipping 688 matching lines @@
           'i18n/time_formatting.h',
           'i18n/timezone.cc',
           'i18n/timezone.h',
           'i18n/utf8_validator_tables.cc',
           'i18n/utf8_validator_tables.h',
         ],
       }]
     ],
   },
 }