See https://bugs.chromium.org/p/chromium/issues/detail?id=713423#c11 for an example where bugdroid failed to update crbug on landing of a merge commit.

The merge commit contained a reference to the crbug in a BUG= line, and bugdroid *did* add a comment to the bug on landing the earlier ToT version of the patch (https://bugs.chromium.org/p/chromium/issues/detail?id=713423#c6).

This bug is to track investigating/fixing why bugdroid didn't comment appropriately on the landing of the merge-to-m59 commit in  bug 713423 .