Removes the IsReadingListEnabled flags

ios/chrome/browser/ui/ntp/BUILD.gn

 # 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.
 
 bundle_data("resources") {
   sources = [
     "resources/bookmarks_bar_bg.png",
     "resources/bookmarks_bar_bg@2x.png",
     "resources/bookmarks_bar_bg@2x~ipad.png",
     "resources/bookmarks_bar_bg_pressed@2x~ipad.png",
@@ skipping 139 matching lines @@
     "//base:i18n",
     "//components/favicon/core",
     "//components/favicon_base",
     "//components/google/core/browser",
     "//components/history/core/browser",
     "//components/keyed_service/core",
     "//components/metrics",
     "//components/ntp_tiles",
     "//components/prefs",
     "//components/rappor",
-    "//components/reading_list/core:flags",
     "//components/search_engines",
     "//components/strings",
     "//components/suggestions",
     "//components/sync_sessions",
     "//components/toolbar",
     "//ios/chrome/app/strings",
     "//ios/chrome/app/theme",
     "//ios/chrome/browser",
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/favicon",
@@ skipping 103 matching lines @@
     "new_tab_page_perftest.mm",
   ]
   deps = [
     "//base/test:test_support",
     "//ios/chrome/browser/sessions",
     "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/test:perf_test_support",
     "//ios/chrome/browser/ui:ui_internal",
   ]
 }