Thank you for letting me know that you also are getting visits from my US/Mac/Chrome visitor, Tahirhabib684. At the moment, you seem to be the only other person apart from me who has noticed this visitor though!
It is certainly a possibility that this might be something to do with Google/Blogger. However, if this was the case you
would expect this (presumably automated) visitor to be consistent and visit every post published.
My visitor does indeed usually visit ever post immediately.... but not always! Very occasionally, several hours have passed before he has turned up (I'll call the visitor 'him' here as it is easier to do so - although I do not know if the visitor is male or female, an automated bot or an alien from outer space! ) There was an unused blog of mine where I would frequently test him by just changing the tiniest detail e.g. just adding a full stop to the title. At first, he came along every time these small changes were made..... but then he seemed to get wise to what I was doing and would only visit about once a day, no matter how many times I made changes.
Again, he usually visits new blogs immediately they come into existence. However, I recently created a new blog which he did not find for two days, despite me publishing several test posts. I really thought I had succeeded in managing to create a blog where he was not present and I was so disappointed when he finally turned up! He was viewing posts on my other blogs during this 2-day period, so it was not a question of this person (or bot) being absent or offline.
The idea of Google being involved in this is however a very interesting one, as I have also been getting visits from a strange Google proxy. This google-proxy apparently uses IP numbers legitimately owned by Google, so is presumably one of the proxies actually used by Google. This proxy is always shown as using Internet Explorer, but with a variety of versions of Windows Operating Systems and Browsers. (Rather curiously, the earliest Operating System shown was Windows xP when the proxy visited a language website of mine - not a blog - twice on Christmas day 2014!). I have no idea whatsoever why this proxy would want to visit my blogs, but I do know that on two or three occasions on which I mentioned this proxy on a blog of mine, the person using the proxy responded instantly by visiting my blog within just one or two minutes of the post being published..... immediately following a visit from the US/Macintosh/Chrome user. The first time this happened, the proxy revisited a few hours afterwards and this was the one-and-only occasion when it displayed the US/Macintosh/Chrome credentials!
I will probably never know exactly what has been going on here: there does not seem to be any answer which entirely makes sense!