Make browsing_data component a layered component

components/browsing_data/pref_names.h

Index: components/browsing_data/pref_names.h
diff --git a/components/browsing_data/pref_names.h b/components/browsing_data/pref_names.h
deleted file mode 100644
index 8ee1e8ca19e953aa8b8e5f337756abf7a876d2e7..0000000000000000000000000000000000000000
--- a/components/browsing_data/pref_names.h
+++ /dev/null
@@ -1,27 +0,0 @@
-// 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.
-
-#ifndef COMPONENTS_BROWSING_DATA_PREF_NAMES_H_
-#define COMPONENTS_BROWSING_DATA_PREF_NAMES_H_
-
-namespace browsing_data {
-
-namespace prefs {
-
-extern const char kDeleteTimePeriod[];
-
-extern const char kDeleteBrowsingHistory[];
-extern const char kDeleteDownloadHistory[];
-extern const char kDeleteCache[];
-extern const char kDeleteCookies[];
-extern const char kDeletePasswords[];
-extern const char kDeleteFormData[];
-extern const char kDeleteHostedAppsData[];
-extern const char kDeleteMediaLicenses[];
-
-}  // namespace prefs
-
-}  // namespace browsing_data
-
-#endif  // COMPONENTS_BROWSING_DATA_PREF_NAMES_H_