bug#65888: region on pixel-scroll-precision-mode

[Tak Kunihiro]

Dear pixel-scroller (Dear Po Lu),

The pixel-scroll-precision-mode maintains active region
and this behavior could be useful.

However at the same time, PSPM provides more than pixel scrolling.
Should this be provided as option? 

1. emacs -Q
2. Make region active
3. Scroll using mouse wheel
4. Then region is deactivated

5. M-x pixel-scroll-precision-mode
6. Make region active
7. Scroll using mouse wheel
8. Then region expands as scroll down and up

Tak