Revert of [Sync] Adds a new switch for enabling the new local server backend.

components/sync/engine/sync_manager.h

Index: components/sync/engine/sync_manager.h
diff --git a/components/sync/engine/sync_manager.h b/components/sync/engine/sync_manager.h
index 6ee8e03c7dea50da69ac77329a573d7532b1a871..71bfcdc845f54d1b2fd1b2929386300cd4b1755d 100644
--- a/components/sync/engine/sync_manager.h
+++ b/components/sync/engine/sync_manager.h
@@ -224,11 +224,6 @@
     // URL of the sync server.
     GURL service_url;
 
-    // Whether the local backend provided by the LoopbackServer should be used
-    // and the location of the local sync backend storage.
-    bool enable_local_sync_backend;
-    base::FilePath local_sync_backend_folder;
-
     // Used to communicate with the sync server.
     std::unique_ptr<HttpPostProviderFactory> post_factory;