Start the migration of passwords from the Keychain.

components/password_manager/core/browser/password_manager.cc

Index: components/password_manager/core/browser/password_manager.cc
diff --git a/components/password_manager/core/browser/password_manager.cc b/components/password_manager/core/browser/password_manager.cc
index fb8178bc02c49ada89127b90f3aa58ee54d92117..e35c99220a5e9ef09fb00011b830d8446bbb6563 100644
--- a/components/password_manager/core/browser/password_manager.cc
+++ b/components/password_manager/core/browser/password_manager.cc
@@ -142,6 +142,10 @@ void PasswordManager::RegisterProfilePrefs(
   registry->RegisterBooleanPref(prefs::kPasswordManagerAllowShowPasswords,
                                 true);
   registry->RegisterListPref(prefs::kPasswordManagerGroupsForDomains);
+#if defined(OS_MACOSX)
+  registry->RegisterIntegerPref(prefs::kKeychainMigrationStatus,
+                                static_cast<int>(MigrationStatus::NOT_STARTED));
+#endif
 }
 
 #if defined(OS_WIN)