Migrate Extensions code to Task Scheduler API

chrome/browser/extensions/api/storage/settings_sync_util.cc

Index: chrome/browser/extensions/api/storage/settings_sync_util.cc
diff --git a/chrome/browser/extensions/api/storage/settings_sync_util.cc b/chrome/browser/extensions/api/storage/settings_sync_util.cc
index e29718c43f4a593c99230337ba1b709fa4e24205..cfde73aebc3a25fe0ed88b6ad656b4f8d249acc0 100644
--- a/chrome/browser/extensions/api/storage/settings_sync_util.cc
+++ b/chrome/browser/extensions/api/storage/settings_sync_util.cc
@@ -10,11 +10,9 @@
 #include "components/sync/protocol/app_setting_specifics.pb.h"
 #include "components/sync/protocol/extension_setting_specifics.pb.h"
 #include "components/sync/protocol/sync.pb.h"
-#include "content/public/browser/browser_thread.h"
+#include "extensions/browser/api/storage/backend_task_runner.h"
 #include "extensions/browser/api/storage/storage_frontend.h"
 
-using content::BrowserThread;
-
 namespace extensions {
 
 namespace settings_sync_util {
@@ -112,7 +110,7 @@ syncer::SyncChange CreateDelete(
 
 syncer::SyncableService* GetSyncableService(content::BrowserContext* context,
                                             syncer::ModelType type) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK(IsOnBackendSequence());
   DCHECK(type == syncer::APP_SETTINGS || type == syncer::EXTENSION_SETTINGS);
   StorageFrontend* frontend = StorageFrontend::Get(context);
   SyncValueStoreCache* sync_cache = static_cast<SyncValueStoreCache*>(