Add a new function for getting a deterministic machine ID

chrome/chrome_tests_unit.gypi

 # Copyright 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': {
     'chrome_unit_tests_sources': [
       '../components/autofill/content/renderer/test_password_autofill_agent.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.h',
       '../components/autofill/content/renderer/test_password_generation_agent.cc',
       '../components/autofill/content/renderer/test_password_generation_agent.h',
@@ skipping 172 matching lines @@
       'browser/prefs/command_line_pref_store_unittest.cc',
       'browser/prefs/incognito_mode_prefs_unittest.cc',
       'browser/prefs/leveldb_pref_store_unittest.cc',
       'browser/prefs/pref_model_associator_unittest.cc',
       'browser/prefs/prefs_syncable_service_unittest.cc',
       'browser/prefs/profile_pref_store_manager_unittest.cc',
       'browser/prefs/proxy_config_dictionary_unittest.cc',
       'browser/prefs/proxy_policy_unittest.cc',
       'browser/prefs/proxy_prefs_unittest.cc',
       'browser/prefs/session_startup_pref_unittest.cc',
+      'browser/prefs/tracked/device_id_unittest.cc',
       'browser/prefs/tracked/mock_validation_delegate.cc',
       'browser/prefs/tracked/mock_validation_delegate.h',
       'browser/prefs/tracked/pref_hash_calculator_unittest.cc',
       'browser/prefs/tracked/pref_hash_filter_unittest.cc',
       'browser/prefs/tracked/pref_hash_store_impl_unittest.cc',
       'browser/prefs/tracked/pref_service_hash_store_contents_unittest.cc',
       'browser/prefs/tracked/segregated_pref_store_unittest.cc',
       'browser/prefs/tracked/tracked_preferences_migration_unittest.cc',
       'browser/prerender/prerender_history_unittest.cc',
       'browser/prerender/prerender_tracker_unittest.cc',
@@ skipping 2546 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }