Refactor SwipeDetector to track both axes

Existing clients now use the SingleAxisSwipeDetector subclass. A
followup CL will add BothAxesSwipeDetector, whose first client will be
the quick switch from home controller.

Bug: 126596417
Change-Id: I54c71088cfe99ff28cdc719a1eb7a7d06ac95d2d
Merged-In: I54c71088cfe99ff28cdc719a1eb7a7d06ac95d2d