Enable RL sync by default on iOS

components/reading_list/reading_list_pref_names.h

Index: components/reading_list/reading_list_pref_names.h
diff --git a/components/reading_list/reading_list_pref_names.h b/components/reading_list/reading_list_pref_names.h
deleted file mode 100644
index b5c82afd7322e56a56babfbc907aadd212fc7c41..0000000000000000000000000000000000000000
--- a/components/reading_list/reading_list_pref_names.h
+++ /dev/null
@@ -1,18 +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.
-
-// Constants for the names of various reading list preferences.
-
-#ifndef COMPONENTS_READING_LIST_READING_LIST_PREF_NAMES_H_
-#define COMPONENTS_READING_LIST_READING_LIST_PREF_NAMES_H_
-
-namespace reading_list {
-namespace prefs {
-
-extern const char kReadingListHasUnseenEntries[];
-
-}  // namespace prefs
-}  // namespace reading_list
-
-#endif  // COMPONENTS_READING_LIST_READING_LIST_PREF_NAMES_H_