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

chrome/browser/net/file_downloader_unittest.cc

 // 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.
 
-#include "chrome/browser/net/file_downloader.h"
-
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
-#include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "chrome/browser/net/file_downloader.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 const char kURL[] = "https://www.url.com/path";
 const char kFilename[] = "filename.ext";
 const char kFileContents1[] = "file contents";
@@ skipping 99 matching lines @@
   ASSERT_TRUE(base::ReadFileToString(path(), &contents));
   EXPECT_EQ(std::string(kFileContents1), contents);
 
   SetValidResponse2();
   Download(false, FileDownloader::EXISTS);
   // The file should still have the old contents.
   EXPECT_TRUE(base::PathExists(path()));
   ASSERT_TRUE(base::ReadFileToString(path(), &contents));
   EXPECT_EQ(std::string(kFileContents1), contents);
 }