Revert of Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

ios/chrome/browser/ui/first_run/first_run_util.mm

 // Copyright 2014 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 "ios/chrome/browser/ui/first_run/first_run_util.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/sys_string_conversions.h"
-#include "base/threading/sequenced_worker_pool.h"
 #include "base/time/time.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #import "ios/chrome/browser/crash_report/breakpad_helper.h"
 #include "ios/chrome/browser/first_run/first_run.h"
 #import "ios/chrome/browser/first_run/first_run_configuration.h"
 #include "ios/chrome/browser/first_run/first_run_metrics.h"
 #include "ios/chrome/browser/signin/signin_manager_factory.h"
 #include "ios/chrome/browser/tabs/tab.h"
 #include "ios/chrome/browser/ui/first_run/first_run_histograms.h"
@@ skipping 161 matching lines @@
                                        base::TimeDelta::FromMinutes(3), 50);
 }
 
 void FirstRunDismissed() {
   [[NSNotificationCenter defaultCenter]
       postNotificationName:kChromeFirstRunUIDidFinishNotification
                     object:nil];
 }
 
 }  // namespace ios_internal