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

ios/chrome/today_extension/today_metrics_logger.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.
 
 #import <UIKit/UIKit.h>
 
 #import "ios/chrome/today_extension/today_metrics_logger.h"
 
 #include "base/base64.h"
 #include "base/cpu.h"
 #include "base/mac/bind_objc_block.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/metrics/histogram_base.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
-#include "base/threading/sequenced_worker_pool.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_log_uploader.h"
 #include "components/metrics/metrics_pref_names.h"
 #include "components/metrics/metrics_service_client.h"
 #include "components/metrics/net/version_utils.h"
 #include "components/prefs/json_pref_store.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/prefs/pref_service_factory.h"
 #include "components/prefs/value_map_pref_store.h"
@@ skipping 264 matching lines @@
 void TodayMetricsLogger::UniqueInconsistencyDetected(
     base::HistogramBase::Inconsistency problem) {
   UMA_HISTOGRAM_ENUMERATION("Histogram.InconsistenciesBrowserUnique", problem,
                             base::HistogramBase::NEVER_EXCEEDED_VALUE);
 }
 
 void TodayMetricsLogger::InconsistencyDetectedInLoggedCount(int amount) {
   UMA_HISTOGRAM_COUNTS("Histogram.InconsistentSnapshotBrowser",
                        std::abs(amount));
 }