profiler: cleanup unused alternate_timer code

tools/gn/bootstrap/bootstrap.py

 #!/usr/bin/env python
 # Copyright 2014 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 file isn't officially supported by the Chromium project. It's maintained
 # on a best-effort basis by volunteers, so some things may be broken from time
 # to time. If you encounter errors, it's most often due to files in base that
 # have been added or moved since somebody last tried this script. Generally
 # such errors are easy to diagnose.
@@ skipping 196 matching lines @@
       'base/metrics/sample_map.cc',
       'base/metrics/sample_vector.cc',
       'base/metrics/sparse_histogram.cc',
       'base/metrics/statistics_recorder.cc',
       'base/path_service.cc',
       'base/pending_task.cc',
       'base/pickle.cc',
       'base/process/kill.cc',
       'base/process/process_iterator.cc',
       'base/process/process_metrics.cc',
-      'base/profiler/alternate_timer.cc',
       'base/profiler/tracked_time.cc',
       'base/run_loop.cc',
       'base/sequence_checker_impl.cc',
       'base/sequenced_task_runner.cc',
       'base/sha1_portable.cc',
       'base/strings/pattern.cc',
       'base/strings/string16.cc',
       'base/strings/string_number_conversions.cc',
       'base/strings/string_piece.cc',
       'base/strings/string_split.cc',
@@ skipping 232 matching lines @@
     cmd.append('-v')
   cmd.append('gn')
   check_call(cmd)
 
   if not options.debug:
     check_call(['strip', os.path.join(build_dir, 'gn')])
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))