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

components/os_crypt/key_storage_linux.cc

Index: components/os_crypt/key_storage_linux.cc
diff --git a/components/os_crypt/key_storage_linux.cc b/components/os_crypt/key_storage_linux.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c243a129808d6c8cd850189962ce20d1bfabae07
--- /dev/null
+++ b/components/os_crypt/key_storage_linux.cc
@@ -0,0 +1,17 @@
+// Copyright 2016 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.
+
+#include "components/os_crypt/key_storage_linux.h"
+
+#include "components/os_crypt/key_storage_libsecret.h"
+
+// static
+std::unique_ptr<KeyStorageLinux> KeyStorageLinux::CreateService() {
+  std::unique_ptr<KeyStorageLinux> key_storage(new KeyStorageLibsecret());
+
+  if (key_storage->Init())
+    return key_storage;
+
+  return nullptr;
+}