[I work at Google, not on chrome]
The current text of the whitepaper is
"The combined state of these variations is non-identifying, since it is based on a 13-bit low entropy value (see above). These are transmitted using the "X-Client-Data" HTTP header, which contains a list of active variations"[0].
The X-Client-Data header is still described as non-identifying. You're reaching for controversy where there is none. I've had this conversation with GP before[1], and it's always unenjoyable, because it's like talking to a conspiracy theorist. There's no rational basis for Google doing what you and they suggest that Google is doing. And you're willing to take events that aren't actually evidence of any kind of malaction (like rewording a document to mean essentially the same thing) and try and draw nefarious conclusions out of those things. Like, why?
If you start from the assumption that Google is acting unethically and is entirely untrustworthy, there are tons of other approaches they can take to do fingerprinting that wouldn't be detectable at all. If you're logged in, the entire conversation is moot. If they wanted to track you, they have your google account. So this only matters for logged out users, and even then, the value is marginal even if you assume Google isn't using any other form of nefarious tracking.
And again that all assumes Google is openly lying. If you don't include that in your threat model, well, then, Google probably isn't lying.
[0]: https://www.google.com/chrome/privacy/whitepaper.html#mediad...
[1]: https://news.ycombinator.com/item?id=24040675