[Sync] Switch ModelTypeStore* from blocking pool to post_task.h

components/browser_sync/profile_sync_service.h

Index: components/browser_sync/profile_sync_service.h
diff --git a/components/browser_sync/profile_sync_service.h b/components/browser_sync/profile_sync_service.h
index 88837d3b6edead6a6181b89bd5dbeefc5d2164af..b4e29d8fd0a3a0d1c3da6e6a401bb9ffc03af0d8 100644
--- a/components/browser_sync/profile_sync_service.h
+++ b/components/browser_sync/profile_sync_service.h
@@ -559,12 +559,9 @@ class ProfileSyncService : public syncer::SyncServiceBase,
 
   // Returns a function for |type| that will create a ModelTypeStore that shares
   // the sync LevelDB backend. |base_path| should be set to profile path.
-  // |sequenced_worker_pool| is obtained from content::BrowserThread or
-  // web::WebThread depending on platform.
   static syncer::ModelTypeStoreFactory GetModelTypeStoreFactory(
       syncer::ModelType type,
-      const base::FilePath& base_path,
-      base::SequencedWorkerPool* sequenced_worker_pool);
+      const base::FilePath& base_path);
 
   // Needed to test whether the directory is deleted properly.
   base::FilePath GetDirectoryPathForTest() const;