Index: sync/notifier/ack_tracker.cc |
diff --git a/sync/notifier/ack_tracker.cc b/sync/notifier/ack_tracker.cc |
index 4014672b434631ee5159febc8e838823c4cdb267..3e4767de174b4ac4d0cab8a081c15eb7603349f7 100644 |
--- a/sync/notifier/ack_tracker.cc |
+++ b/sync/notifier/ack_tracker.cc |
@@ -95,6 +95,7 @@ void AckTracker::Clear() { |
void AckTracker::Track(const ObjectIdSet& ids) { |
DCHECK(thread_checker_.CalledOnValidThread()); |
+ DCHECK(!ids.empty()); |
scoped_ptr<Entry> entry(new Entry( |
create_backoff_entry_callback_.Run(&kDefaultBackoffPolicy), ids)); |