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

chrome/browser/chromeos/policy/dm_token_storage.cc

 // 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.
 
 #include "chrome/browser/chromeos/policy/dm_token_storage.h"
 
 #include "base/bind.h"
-#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/chromeos/settings/token_encryptor.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/cryptohome/system_salt_getter.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace {
 
 std::string EncryptToken(const std::string& system_salt,
@@ skipping 157 matching lines @@
     return;
   if (dm_token.empty())
     DLOG(ERROR) << "Failed to retrieve DM token.";
   std::vector<RetrieveCallback> callbacks;
   callbacks.swap(retrieve_callbacks_);
   for (RetrieveCallback& callback : callbacks)
     std::move(callback).Run(dm_token);
 }
 
 }  // namespace policy