That's ok. If this plan works, a few years down the road Ublock will get dropped/disabled for you under some pretense when Google can claim they've got you covered for "ad blocking".
You're thinking far too 1984 when the answer is much more Brave New World - if the ad blocker in Chrome is good enough, people will just stop supporting UBlock.
Naw, Google has precedent for this sort of behavior, going so far as removing plugins from their web store and quietly uninstalling them from Chrome with no notification when the plugin interfered with their business model. They actively uninstalled video download plugins without notification to the user a couple years back. Nefarious.
I think you are severely misunderstanding the situation. Google can do whatever they want. They've already demonstrated that they have no problem installing things on your computer that you never would have otherwise agreed to. That, and they don't take no for an answer with updates.
Yes, it's possible—I would say probable—that after introducing their "impartial" ad blocker, whose rules for acceptable ads just so happen to allow all of their ads through, and after enabling it by default on their browser, they will actively block all other ad blockers, on "privacy and security" grounds.
If, by any chance, someone decide that its browser is already covered as far as adblockering goes, we will simply move to a different browser/adblocker/adblocking solution.
As long as there is tech savy people there will be plenty of solutions around.
AdBlock Plus is also open-source. Same license as uBlock Origin and everything.
They just haven't pissed off anyone enough to get a big fork going. Or their code just wasn't good enough, as obviously uBlock Origin is currently doing the same and was written from scratch.