Removes the IsReadingListEnabled flags

ios/chrome/browser/experimental_flags.mm

 // 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.
 
 // This file can be empty. Its purpose is to contain the relatively short lived
 // definitions required for experimental flags.
 
 #include "ios/chrome/browser/experimental_flags.h"
 
 #include <dispatch/dispatch.h>
 #import <Foundation/Foundation.h>
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/autofill/core/common/autofill_switches.h"
-#include "components/reading_list/core/reading_list_switches.h"
 #include "components/variations/variations_associated_data.h"
 #include "ios/chrome/browser/chrome_switches.h"
 #include "ios/web/public/web_view_creation_util.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 namespace {
 
@@ skipping 181 matching lines @@
       base::FieldTrialList::FindFullName("PhysicalWebEnabled");
   return base::StartsWith(group_name, "Enabled",
                           base::CompareCase::INSENSITIVE_ASCII);
 }
 
 bool IsReaderModeEnabled() {
   return base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableReaderModeToolbarIcon);
 }
 
-bool IsReadingListEnabled() {
-  return reading_list::switches::IsReadingListEnabled();
-}
-
 bool IsSafariVCSignInEnabled() {
   return ![[NSUserDefaults standardUserDefaults]
       boolForKey:kSafariVCSignInDisabled];
 }
 
 bool IsStartupCrashEnabled() {
   return [[NSUserDefaults standardUserDefaults] boolForKey:kEnableStartupCrash];
 }
 
 bool IsTabStripAutoScrollNewTabsEnabled() {
@@ skipping 26 matching lines @@
     return true;
 
   if (command_line->HasSwitch(switches::kDisableSuggestionsUI))
     return false;
 
   // By default, disable it.
   return false;
 }
 
 }  // namespace experimental_flags