Removes the IsReadingListEnabled flags

ios/chrome/app/BUILD.gn

 # 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.
 
 import("//build/config/ios/rules.gni")
 import("//build/config/mac/base_rules.gni")
 import("//build/mac/tweak_info_plist.gni")
 import("//ios/build/chrome_build.gni")
 import("//ios/public/provider/chrome/browser/build_config.gni")
 
@@ skipping 131 matching lines @@
     "//components/favicon/core",
     "//components/favicon_base",
     "//components/handoff",
     "//components/history/core/browser",
     "//components/infobars/core",
     "//components/keyed_service/core",
     "//components/keyed_service/ios",
     "//components/metrics",
     "//components/prefs",
     "//components/proxy_config",
-    "//components/reading_list/core:flags",
     "//components/signin/core/browser",
     "//components/suggestions",
     "//components/sync",
     "//components/url_formatter",
     "//components/web_resource",
     "//ios/chrome/app/application_delegate",
     "//ios/chrome/app/application_delegate:application_delegate_internal",
     "//ios/chrome/app/safe_mode",
     "//ios/chrome/app/spotlight",
     "//ios/chrome/app/startup",
@@ skipping 179 matching lines @@
       ]
       sources = [
         "$root_out_dir/share_extension.appex",
       ]
       outputs = [
         "{{bundle_plugins_dir}}/{{source_file_part}}",
       ]
     }
   }
 }