Just a reminder: You get the same harmonic at the 19th fret and at the 7th.
Also, you get the same harmonic at the 19th fret whether the string is fretted at the 7th or is open. I believe Vidovic transitions from one to the other method in that passage.
Other concert players, as you can see on youtube, prefer the 7th fret harmonic there. That makes a lot of sense because the index finger is already there at the 7th, but I could never make that little transition sound smooth. I wish I could do it that way, because it seems like fewer moving parts to me, which means fewer things that can go wrong, but I do it the same way Vidovic does because for me it comes out smoother. YMMV.