Removes the IsReadingListEnabled flags

ios/chrome/browser/ui/toolbar/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/collapse.png",
     "resources/collapse@2x.png",
     "resources/collapse@3x.png",
     "resources/collapse_incognito.png",
@@ skipping 52 matching lines @@
   deps = [
     ":resource_macros",
     ":resources",
     "//base",
     "//base:i18n",
     "//components/bookmarks/browser",
     "//components/google/core/browser",
     "//components/omnibox/browser",
     "//components/prefs",
     "//components/reading_list/core",
-    "//components/reading_list/core:flags",
     "//components/reading_list/ios",
     "//components/search_engines",
     "//components/strings",
     "//components/toolbar",
     "//ios/chrome/app/strings",
     "//ios/chrome/app/theme",
     "//ios/chrome/browser",
     "//ios/chrome/browser/autocomplete",
     "//ios/chrome/browser/bookmarks",
     "//ios/chrome/browser/browser_state",
@@ skipping 110 matching lines @@
     "//ios/chrome/browser/ui/tools_menu",
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing/earl_grey:earl_grey_support",
     "//ios/third_party/earl_grey",
     "//ios/web:test_support",
     "//ui/base",
   ]
   libs = [ "XCTest.framework" ]
 }