I have this CL that changes layout tests only:
https://chromium-review.googlesource.com/c/558385/2

In PS#1, I triggered linux_trusty_blink_rel and the run was here:
https://build.chromium.org/p/tryserver.blink/builders/linux_trusty_blink_rel/builds/11698

you can see it says "compile (with patch) confirm no-op compile (with patch) confirm no-op"

But PS#2 here: https://build.chromium.org/p/tryserver.blink/builders/linux_trusty_blink_rel/builds/11709

triggers compilation.

PTAL