Start the migration of passwords from the Keychain.

components/password_manager/core/browser/keychain_migration_status_mac.h

+// Copyright 2015 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.
+
+#ifndef COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_KEYCHAIN_MIGRATION_STATUS_MAC_H
+#define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_KEYCHAIN_MIGRATION_STATUS_MAC_H
+
+namespace password_manager {
+
+// Status of password migration from the Keychain.
+// The enum is used to back a histogram, and should therefore be treated as
+// append-only.
+enum class MigrationStatus {
+  // Migration wasn't tried yet.
+  NOT_STARTED = 0,
+
+  // Migration finished successfully.
+  MIGRATED,
+
+  // Migration failed once. It should be tried again.
+  FAILED_ONCE,
+
+  // Migration failed twice. It should not be tried again.
+  FAILED_TWICE,
+
+  MIGRATION_STATUS_COUNT,
+};
+
+}  // namespace password_manager
+
+#endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_KEYCHAIN_MIGRATION_STATUS_MAC_H