Migrate show when lock behavior to handleRequset

Current show when lock behavior implementation sometimes doesn't
work due to both tasks are invisible and lead to the app could
only show half of screen.
Because show when lock it will get a TRANSIT_KEYGUARD_OCCLUDE
transition so we can handle it on the handleRequest and it will
also make the transition more smooth.

Fix: 284253219
Test: manual
Test: pass existing tests
Change-Id: I5a7f364a732faa26e9021054180bab40a1faaafe