Are their tanks in raids?

I know GW2 doesnt have a trinity but is there a profession that tanks in T-4 Fractuals and raids? One where the dps is lower but they put out a lot of defensives. Or is it a lot of healing from druids and DPS zerg? Never done one...I have played a tank in most games and really missing it currently.

Fractals not so much. Riads depend on the boss. Bosses like vg and gors agro to the person with the highest toughness, bosses like sloth assigns agro to a random person and changes it periodically, cairn agros to the person furthest away from it.

What classes are considered the meta tanks then? Top two actually?

There really is not even a "top 2". The go-to Raid Tank is Chronomancer or nothing (Except a few bosses that want a Kiter instead), but not for the reason you might think.

Basically, Tanking in Raids is determined by different factors and for a few of those, the players can choose their own tank (other bosses uses different Aggro mechanics, such as Distance or Random Rotation). These bosses are the ones that typically Aggro on the highest Toughness, so you simply kit out any profession in high Toughness gear and tank away. And when you can do this, the profession of choice is always Chronomancer, because:

A/ Chronomancer's DPS is utterly deplorable. It struggles to even pull a third or a fourth of dedicated DPS slots' weight in terms of raw damage. As such, if you're gonna have a Chrono, it's not for DPS.

B/ Chronomancers have absolutely godly support and utility, so much that you're pretty much gauranteed to want at least 1 of them for every Raid Boss.

C/ Chronomancers can Distort themselves and have access to a 2 1/2s Invulnerability on an 8s Cooldown. This ability can evade just about -everything- in the game with a few exceptions, which you'll soon learn after getting into raids.

With these 3 points in mind, you can see how there's basically no point in taking a Chrono along for the ride without making them your tank (Unless you have 2 of them, but even then they're just there for their support and utility.) And if you've already got a Chrono for a tank, there's no need to spec anything else for Tanking since you don't need more than one (With current bosses and mechanics.)

Fair warning though, if you're planning on tanking: Mesmer has a high skill floor and skill ceiling to get down, Chronomancer even more so. And gearing them up is either grindy, expensive or both depending on how you do it. And that's before learning how to actually tank each specific boss you can tank.