[Macuyiko]

Not really. All of these are mostly user agent modifications to pretend to be Chrome to make certain sites work, as well as some JavaScript event modification (with a similar purpose).

The only "shady" thing is hiding the Chrome ad on Google's home page, though I guess you can consider that as a convenience once you decide to switch fully to another browser.

I don't know how easy it would be to pull an update for that file however, in which case it could become shady in an instant.

[neotek]

Why would they need to update browser.js to do something shady, they can just drop in a brand new binary that does whatever they want it to do and the vast majority of users would be none the wiser.