Having a separate test apk from the apk_under_test makes sense when the under_test apk is a production apk. However, there's not much point in having an under_test apk that is only for testing purposes. We should just merge chrome_public_for_test_apk into chrome_public_test_apk.
Similar bug for merging with chrome_sync_shell: bug 833545
Comment 1 by jbudorick@chromium.org
, May 10 2018