Prevent addtional removeSurface calls

The surface may not be cleared by its owner when
it lose control last time. We had CL[1] to clean
up the surface if we don't plan to show.

Add new checking condition for last control, so
once we have control we only remove the surface
if last control was null.

[1]: I4910c2a06cc67b0470477b245fc1de54b75f10f9

Bug: 185557884
Test: atest InsetsSourceConsumerTest
Change-Id: I1a4f05f9b4cf6fa121554ff0abc9fdc418b95276