Revert "Consider UID instead of PID in canBeObscuredBy()"

This reverts commit dc8c2c659f54dd54aaa9ced58c0acd7fbd801a58.

Reason for revert: Broke tests (b/169243733)

Change-Id: I854b4b6ed94065bfb67a0e30742209aed57ac1e3
1 file changed