[Sync] ModelTypeStore factory shouldn't require valid PSS to function correctly

chrome/browser/sync/profile_sync_service_factory.cc

Index: chrome/browser/sync/profile_sync_service_factory.cc
diff --git a/chrome/browser/sync/profile_sync_service_factory.cc b/chrome/browser/sync/profile_sync_service_factory.cc
index 57d9f22f04d1b96117691db04a55dfd4cc1db56a..cfcc5340af7ece833bbfa45f7e682306ace77df5 100644
--- a/chrome/browser/sync/profile_sync_service_factory.cc
+++ b/chrome/browser/sync/profile_sync_service_factory.cc
@@ -149,12 +149,6 @@ KeyedService* ProfileSyncServiceFactory::BuildServiceInstanceFor(
   init_params.url_request_context = profile->GetRequestContext();
   init_params.debug_identifier = profile->GetDebugName();
   init_params.channel = chrome::GetChannel();
-  base::SequencedWorkerPool* blocking_pool =
-      content::BrowserThread::GetBlockingPool();
-  init_params.blocking_task_runner =
-      blocking_pool->GetSequencedTaskRunnerWithShutdownBehavior(
-          blocking_pool->GetSequenceToken(),
-          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
 
   if (!client_factory_) {
     init_params.sync_client =