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

chrome/browser/chromeos/base/file_flusher_unittest.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/base/file_flusher.h"
 
 #include <map>
 #include <memory>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chromeos {
 
 namespace {
 
 void WriteStringToFile(const base::FilePath path, const std::string& data) {
   ASSERT_TRUE(base::CreateDirectory(path.DirName()))
@@ skipping 117 matching lines @@
                         run_loop.QuitClosure());
   flusher->ResumeForTest();
   run_loop.Run();
 
   EXPECT_EQ(1, GetFlushCount("dir1/file1"));
   EXPECT_EQ(1, GetFlushCount("dir1/file2"));
   EXPECT_EQ(1, GetFlushCount("dir1/file3"));
 }
 
 }  // namespace chromeos