To run the scrolling benchmark on a device:
flutter drive --profile test_driver/scroll_perf.dart
Results should be in the file build/platform_views_scroll_perf.timeline_summary.json.
More detailed logs should be in build/platform_views_scroll_perf.timeline.json.
To measure startup time on a device:
flutter run --profile --trace-startup
Results should be in the logs.
Additional results should be in the file build/start_up_info.json.