Revert of file_manager: Migrate FILE thread to TaskScheduler

chrome/browser/chromeos/extensions/file_manager/file_browser_handler_api_test.cc

 // Copyright (c) 2012 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.
 
 // File contains browser tests for the fileBrowserHandler api.
 
 #include "chrome/browser/chromeos/extensions/file_manager/file_browser_handler_api.h"
 
 #include <stddef.h>
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
-#include "base/task_scheduler/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/extensions/extension_function_test_utils.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/browser_context.h"
 #include "extensions/browser/api_test_utils.h"
@@ skipping 267 matching lines @@
   ui_test_utils::NavigateToURL(browser(), url);
 
   ASSERT_TRUE(catcher.GetNextResult()) << message_;
 
   // Selected path should have been created by the test extension after the
   // extension function call.
   ASSERT_TRUE(base::PathExists(selected_path));
 
   // Let's check that the file has the expected content.
   const std::string expected_contents = "hello from test extension.";
-  base::PostTaskWithTraits(FROM_HERE,
-                           {base::MayBlock(), base::TaskPriority::USER_VISIBLE},
-                           base::BindOnce(&ExpectFileContentEquals,
-                                          selected_path, expected_contents));
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE, FROM_HERE,
+      base::BindOnce(&ExpectFileContentEquals, selected_path,
+                     expected_contents));
 
   // Make sure test doesn't finish until we check on file thread that the
   // selected file's content is as expected.
   content::RunAllPendingInMessageLoop(content::BrowserThread::FILE);
 
   SetTestCases(NULL);
 }
 
 // Tests that verifies the fileBrowserHandlerInternal.selectFile function fails
 // when invoked without user gesture.
@@ skipping 65 matching lines @@
           select_file_function.get(),
           "[{\"suggestedName\": \"/path_to_file/some_file_name.txt\"}]",
           browser())));
 
   EXPECT_FALSE(extensions::api_test_utils::GetBoolean(result.get(), "success"));
   base::DictionaryValue* entry_info;
   EXPECT_FALSE(result->GetDictionary("entry", &entry_info));
 }
 
 }  // namespace