In the latest trailer a line is delivered at around 1:41 where Han Solo says "a 190 years old!? You look great" and I was wondering if there is a defined concept of a year in the Star Wars universe or would Han Solo just be familiar with the duration of a Kashyyyk solar orbit.
A Galactic Standard Year is based on the Galactic Capital, Coruscant.
On Coruscant, a year was made up of twelve months spanning 365 days of 24 hours each, with no leap years. The galaxy used a standardized dating system based off of the galactic capital Coruscant.
Standard Year | Wookieepedia
This is confirmed by Pablo Hidalgo in Rebels Recon (a behind the scenes show for Star Wars: Rebels)
Q: Nolan Jimenez asks, "How is time measured in the galaxy if each planet has a different time of rotation and translation?"
A: We kinda assume that there is a standard hour, a standard day, a standard week, a standard month, a unit of measurement that everyone understand how long that is. And in our storytelling we say that unit of measurement comes from Coruscant. So not only is it the galactic capital, it is sorta the yardstick through which all time is measured in the galaxy.
This is the same in both Canon and Legends.
As per years of Star Wars Extended Universe canon, the GFFA definitely has a Galactic Standard Year. While much of this is now 'Legends', the year convention of "[Years] After Battle of Yavin" and "[Years] Before Battle of Yavin" seems to still be canon, which means definitely standard years exist, and as per Legends this was Coruscant Standard Year (365 standard days of 24 standard hours), presumably based on the revolution of the galactic capital.
Kashyyyk has been a Republic planet for many many years, so there's no more reason to assume that Chewbacca is telling his age in Kashyyyk solar years, rather than Galactic Standard, than there would be to assume that a random person telling you the time is telling you the local solar time as opposed to standard time-zone time.
As per Legends, a Wookiee's average lifespan is 400 (Galactic Standard) years. Chewie was born 200 BBY, and since the new movie trailer seems to corroborate that, that means the 200 BBY date of birth for Chewie is canon again.
(Btw: It seems to be canon again that Kashyyyk's orbital period is 381 (galactic standard) days, but this has nothing to do with Chewie's age.)