[Sync] Sync client should to exponential backoff when receive partial failure

components/sync/engine_impl/get_updates_processor.cc

Index: components/sync/engine_impl/get_updates_processor.cc
diff --git a/components/sync/engine_impl/get_updates_processor.cc b/components/sync/engine_impl/get_updates_processor.cc
index 3dc9cb5ca2ab8f78cac05d8fc9e897c9f5932558..eaa6c92e100dde88399a3fc06bf1810c40ef0575 100644
--- a/components/sync/engine_impl/get_updates_processor.cc
+++ b/components/sync/engine_impl/get_updates_processor.cc
@@ -76,9 +76,9 @@ void PartitionUpdatesByType(const sync_pb::GetUpdatesResponse& gu_response,
 
     TypeSyncEntityMap::iterator it = updates_by_type->find(type);
     if (it == updates_by_type->end()) {
-      DLOG(WARNING)
-          << "Received update for unexpected type or the type is throttled:"
-          << ModelTypeToString(type);
+      DLOG(WARNING) << "Received update for unexpected type, or the type is "
+                       "throttled or failed with partial failure:"
+                    << ModelTypeToString(type);
       continue;
     }