Fix remaining incompatibilities between scoped_ptr and unique_ptr.

sync/sessions/data_type_tracker.cc

Index: sync/sessions/data_type_tracker.cc
diff --git a/sync/sessions/data_type_tracker.cc b/sync/sessions/data_type_tracker.cc
index 63cf523dd674203279b90abbc3dc2ff94fea2e94..4a8d8d022d21ad8680fe2dc3d1d2b6c5e24ab0a1 100644
--- a/sync/sessions/data_type_tracker.cc
+++ b/sync/sessions/data_type_tracker.cc
@@ -202,7 +202,7 @@ void DataTypeTracker::FillGetUpdatesTriggersMessage(
   msg->set_server_dropped_hints(
       !pending_invalidations_.empty() &&
       (*pending_invalidations_.begin())->IsUnknownVersion());
-  msg->set_client_dropped_hints(last_dropped_invalidation_);
+  msg->set_client_dropped_hints(!!last_dropped_invalidation_);
   msg->set_local_modification_nudges(local_nudge_count_);
   msg->set_datatype_refresh_nudges(local_refresh_request_count_);
   msg->set_initial_sync_in_progress(initial_sync_required_);