This is nuts. On a sidenote, any suggestions for an equivalently fast, secure browser for Android 4.2 on a relatively old phone? Not gonna use AOSP anymore!
You can try Opera Mobile Classic, it's important to use classic version since the new Opera Mobile uses the same engine as chrome so it might have the same vulnerabilities.
Correct. Chrome is a separate project from the AOSP.
That said, Android 4.4 and later use Chromium for their WebViews, the source for which is developed along with Chrome as a part of the Chromium project - it does not live in AOSP.
Presumably the stock browser that is in AOSP 4.4+ wraps Chromium, which more or less means the AOSP browser is Chrome...but not the other way around. :)