Automated tests for the below commit have been missing.Would it be possible to add test coverage to avoid regressions in future?

CL: 
https://chromium.googlesource.com/chromium/src.git/+/db06e65dcd8da3f5b8cab60ecb32e9ba89c1598c

Ref Bug: 
https://bugs.chromium.org/p/chromium/issues/detail?id=727892
Thank you!