OSCrypt for POSIX uses libsecret to store a randomised encryption key.

components/components_tests.gyp

 # 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.
 
 {
   'variables': {
     # This turns on e.g. the filename-based detection of which
     # platforms to include source files on (e.g. files ending in
     # _mac.h or _mac.cc are only compiled on MacOSX).
     'chromium_code': 1,
@@ skipping 1517 matching lines @@
         ['OS=="linux"', {
           'sources': [
             'metrics/serialization/serialization_utils_unittest.cc',
           ],
           'dependencies': [
             'components.gyp:metrics_serialization',
             '../dbus/dbus.gyp:dbus',
             '../device/media_transfer_protocol/media_transfer_protocol.gyp:device_media_transfer_protocol',
           ],
         }],
+        ['OS=="linux" and chromeos!=1', {
+          'sources': [
+            'os_crypt/os_crypt_linux_unittest.cc',
+            'os_crypt/os_crypt_util_linux_unittest.cc',
+          ],
+          'defines': [
+            'USE_LIBSECRET',
+          ],
+          'include_dirs': [
+            '../third_party/libsecret'
+          ],
+        }],
         ['OS=="linux" and use_udev==0', {
           'dependencies!': [
             'components.gyp:storage_monitor',
             'components.gyp:storage_monitor_test_support',
           ],
           'sources/': [
             ['exclude', '^storage_monitor/'],
           ],
         }],
         ['configuration_policy==1', {
@@ skipping 410 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }