If I'm not mistaken the argument for not making Chromium portable was that it only has unstable, nightly builds. Well, is that was the only case against making Chromium an official PortableApps release, I'm happy to report it is simply not a valid case.
Check this out: https://chromium.woolyss.com/
Scroll down to the section:
2. Stable Chromium version
Officially, Chromium does not have a stable release. The official developers (aka The Chromium Authors) do not release it to end users. So it is continually in development. Google Chrome is the stable release... but is not open-source.
In fact, Chromium has a stable version. ^^
Example: The current stable version on #linux is 63.0.3239.132. In this version, there are 132 patches which correct many issues (bugs, feature requests, enhancements...). Because Chromium is open-source (#source-code), anybody can compile it. You must be a developer to do this. Just get the current stable version (63.0.3239.132) from the official Git repository and compile it!
All stable versions of Chromium on #windows, #mac, #linux, #bsd... are always made by third-party developers.
The Chromium stable version is compiled by:
Google developers → Google Chrome and Chrome OS
Opera developers → Opera browser
Yandex developers → Yandex Browser
Nik developer → Chromium, on #windows
FreeSMUG and Marmaduke developers → Chromium, on #mac
Some developers → Chromium, on each #linux and #bsd distribution
Some developers → Chromium-based browsers
Some developers → other projects like CEF, Electron, Atom...
Alternatively, there has been this other project to package Chromium in the PortableApps format, now it's being dormant: http://crportable.sourceforge.net/
So you could literally just pick it up where its maintainer left it. Your thought? Thanks for considering!