b1d17c914d
We've gotten feedback that the VelocityTracker change was disruptive, though it did not break any of the flutter framework or customer tests. In order to make the change non-breaking, PointerDeviceKind parameter can be made optional. Nevertheless, this parameter should be provided so that the existing touch handlers can use more accurate gestures on mouse/stylus inputs, so we can encourage this by deprecating the default constructor and pointing users towards the VelocityTracker.withKind constructor that takes a non-optional parameter
microbenchmarks
To run these benchmarks on a device, first run `flutter logs' in one window to see the device logs, then, in a different window, run any of these:
flutter run --release lib/gestures/velocity_tracker_bench.dart
flutter run --release lib/gestures/gesture_detector_bench.dart
flutter run --release lib/stocks/animation_bench.dart
flutter run --release lib/stocks/build_bench.dart
flutter run --release lib/stocks/layout_bench.dart
The results should be in the device logs.
Avoid changing names of the benchmarks
Each microbenchmark is identified by a name, for example, "catmullrom_transform_iteration". Changing the name of an existing microbenchmarks will effectively remove the old benchmark and create a new one, losing the historical data associated with the old benchmark in the process.