Reland of move header dependencies from sequence_checker.h to sequenced_worker_pool.h

chrome/browser/chromeos/system_logs/debug_log_writer.cc

 // 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.
 
 #include "chrome/browser/chromeos/system_logs/debug_log_writer.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/files/file.h"
 #include "base/files/file_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/common/logging_chrome.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/debug_daemon_client.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace chromeos {
 
 namespace {
 
 // Callback for returning status of executed external command.
@@ skipping 238 matching lines @@
       fileshelf.Append(FILE_PATH_LITERAL("combined-logs.tar"));
 
   // Get system logs from /var/log first, then add user-specific stuff.
   StartLogRetrieval(file_path,
                     false,
                     sequence_token_name,
                     base::Bind(&OnSystemLogsAdded, callback));
 }
 
 }  // namespace chromeos