Update transitions_perf_test.dart (#469)

diff --git a/test_driver/transitions_perf_test.dart b/test_driver/transitions_perf_test.dart
index e0dc681..4f6db12 100644
--- a/test_driver/transitions_perf_test.dart
+++ b/test_driver/transitions_perf_test.dart
@@ -266,7 +266,7 @@
       );
 
       final summary = TimelineSummary.summarize(timeline);
-      await summary.writeSummaryToFile('transitions-crane', pretty: true);
+      await summary.writeTimelineToFile('transitions-crane', pretty: true);
     }, timeout: Timeout.none);
 
     test('only Reply', () async {