Reducing bitmap sizes in notifications

Bitmap sizes could be arbitrary large when they were sent
over to the system. We're now reducing them to reasonable
sizes.s

Also fixed that notification bitmaps were not put into
ashmem anymore since it got lost in a refactor.

Test: code inspection
Bug: 62319200
Merged-In: I87db7656e749666b9eab1f67fd497f155c407e18
Change-Id: I87db7656e749666b9eab1f67fd497f155c407e18