Summary:
When you add new arguments to the unit command, they need to be
threaded through to the unit engine. This enables you to specify passthru
command which will be shipped through the callstack.
Test Plan:
Ran 'arc diff --maxtests 8 --apply-patches --trace' and verified
resulting behavior was correct.
Differential Revision: 207877
Reviewed By: dschleimer
Reviewers: dschleimer
CC: dschleimer
Revert Plan:
OK