Keep track of requestedVisibility when control unavailable

When control is unavailable, but the client still wants to hide or
show something, we keep track of it and execute the animation as
soon as we get control.

Also fix an issue with a crash where control was lost before
animation was started.

Test: InsetsControllerTest, InsetsSourceConsumerTest
Change-Id: I31c5177d9281161b8a607b24ddf094dbba640da3