Don't call surface.remove if surface is null.

This essentially revives the null check removed in
I55e2c1b8fba32b3a19603e6ad4743f07576abd48

Test: N/A
Bug: 64722384
Change-Id: Ifdbc29df54a1a5aedf0e31e0c461146a3e59917d
1 file changed