[Sync] Allow sync start without sign-in if the local sync backend is on.

chrome/browser/history/web_history_service_factory.cc

Index: chrome/browser/history/web_history_service_factory.cc
diff --git a/chrome/browser/history/web_history_service_factory.cc b/chrome/browser/history/web_history_service_factory.cc
index d0149fddb3a553ab87a743540a3669127c5e25ad..a63cedcb83d55b8a477ed4626a3dbdb85c6bd469 100644
--- a/chrome/browser/history/web_history_service_factory.cc
+++ b/chrome/browser/history/web_history_service_factory.cc
@@ -20,9 +20,8 @@ namespace {
 bool IsHistorySyncEnabled(Profile* profile) {
   browser_sync::ProfileSyncService* sync =
       ProfileSyncServiceFactory::GetInstance()->GetForProfile(profile);
-  return sync &&
-      sync->IsSyncActive() &&
-      sync->GetActiveDataTypes().Has(syncer::HISTORY_DELETE_DIRECTIVES);
+  return sync && sync->IsSyncActive() && !sync->IsLocalSyncEnabled() &&
+         sync->GetActiveDataTypes().Has(syncer::HISTORY_DELETE_DIRECTIVES);
 }
 
 }  // namespace