[sf] Set visible regions change flag when layer starts drawing

If a layer state changes so it has a buffer or an effect like
color then, update the flags to indicate that visiblity of a
snapshot has changed. This will mark the visible regions
flag in CE args and force CE to rebuild its layer stack.
Without this flag, there was a scenario where CE
would get a null snapshot and crash.

Also crash early with traces if we ever pass a null snapshot to
CE.

Test: presubmit
Bug: 238781169, 295069311, 294889236
Change-Id: I355502fbe7f1be38c46a5ed25233b6b07c6b4eeb