Enable multiple benign overflow conditions.

In VelocityTracker.cpp, there are multiple loops in which loop
termination occurs when the value becomes zero. These termination
conditions are all written value-- > 0, which, since value is
unsigned, result in an integer overflow condition when value is 0.
These loop were refactored to eliminate these conditions.

Bug: 24171356
Change-Id: Ie44940cfef8a122ee1aff59c021274ba39a368bf