Reland "Make VelocityTracker 1D" (--try 2)

This fixes a bug where stale velocities were not cleaned up during calls
to get updated velocities.
86f72a3882ab4994dfbb410ebebc9ab3a75b8b16

Topic for the revert which is being rolled-forward: https://googleplex-android-review.git.corp.google.com/q/topic:revert-19762050-generic_vt-XWGGUQUHYR

Bug: 32830165
Test: VelocityTracker_test unaffected (atest libinput_tests)

Change-Id: Ib706e76b9502e262eabfd221bd741e5faaee1ed5
diff --git a/include/input/VelocityControl.h b/include/input/VelocityControl.h
index 1acc2ae..f4c7061 100644
--- a/include/input/VelocityControl.h
+++ b/include/input/VelocityControl.h
@@ -98,7 +98,7 @@
     VelocityControlParameters mParameters;
 
     nsecs_t mLastMovementTime;
-    VelocityTracker::Position mRawPosition;
+    float mRawPositionX, mRawPositionY;
     VelocityTracker mVelocityTracker;
 };