Use getOutWindowingMode instead of WINDOWING_MODE_UNDEFINED

If the next windowing mode after a window exits PIP is different from
that of the display, it must be set explicitly instead of just being
reset to WINDOWING_MODE_UNDEFINED.

Bug: 238964721
Test: Manually test PIP on YouTube
Change-Id: I8b70d0032c197a3258695c73e3c3c3f7ed5115ea
1 file changed