Add a dummy entry with libsecret when initializing OSCrypt.

chrome/browser/password_manager/native_backend_libsecret_unittest.cc

Index: chrome/browser/password_manager/native_backend_libsecret_unittest.cc
diff --git a/chrome/browser/password_manager/native_backend_libsecret_unittest.cc b/chrome/browser/password_manager/native_backend_libsecret_unittest.cc
index 466cc9f6ebe0fcf1c8623cea9ecf241af5915183..cc82466fd5cbd5606dfe21c5b814c19371c2f22a 100644
--- a/chrome/browser/password_manager/native_backend_libsecret_unittest.cc
+++ b/chrome/browser/password_manager/native_backend_libsecret_unittest.cc
@@ -98,6 +98,10 @@ gboolean mock_secret_password_store_sync(const SecretSchema* schema,
                                          GCancellable* cancellable,
                                          GError** error,
                                          ...) {
+  // TODO(crbug.com/660005) We don't read the dummy we store to unlock keyring.
+  if (strcmp("_chrome_dummy_schema_for_unlocking", schema->name) == 0)
+    return true;
+
   GHashTable* attributes =
       g_hash_table_new_full(g_str_hash, g_str_equal, g_free, g_free);
   va_list ap;