Revert of Remove SequencedWorkerPool::GetNamedSequenceToken from content::CreateFileSystemContext.

content/browser/fileapi/browser_file_system_helper.cc

Index: content/browser/fileapi/browser_file_system_helper.cc
diff --git a/content/browser/fileapi/browser_file_system_helper.cc b/content/browser/fileapi/browser_file_system_helper.cc
index 9fef5be45db124092bf39ee8a39e0d86e72e8a85..f8da5a6ad26f684a8592e39cfae1dc7ddd741780 100644
--- a/content/browser/fileapi/browser_file_system_helper.cc
+++ b/content/browser/fileapi/browser_file_system_helper.cc
@@ -13,7 +13,7 @@
 #include "base/files/file_path.h"
 #include "base/sequenced_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/task_scheduler/post_task.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
@@ -63,6 +63,12 @@
     const base::FilePath& profile_path,
     bool is_incognito,
     storage::QuotaManagerProxy* quota_manager_proxy) {
+  base::SequencedWorkerPool* pool = BrowserThread::GetBlockingPool();
+  scoped_refptr<base::SequencedTaskRunner> file_task_runner =
+      pool->GetSequencedTaskRunnerWithShutdownBehavior(
+          pool->GetNamedSequenceToken("FileAPI"),
+          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+
   // Setting up additional filesystem backends.
   std::vector<std::unique_ptr<storage::FileSystemBackend>> additional_backends;
   GetContentClient()->browser()->GetAdditionalFileSystemBackends(
@@ -79,10 +85,7 @@
   scoped_refptr<storage::FileSystemContext> file_system_context =
       new storage::FileSystemContext(
           BrowserThread::GetTaskRunnerForThread(BrowserThread::IO).get(),
-          base::CreateSequencedTaskRunnerWithTraits(
-              {base::MayBlock(), base::TaskPriority::BACKGROUND,
-               base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN})
-              .get(),
+          file_task_runner.get(),
           BrowserContext::GetMountPoints(browser_context),
           browser_context->GetSpecialStoragePolicy(), quota_manager_proxy,
           std::move(additional_backends), url_request_auto_mount_handlers,