Both sync[1] and cast[2] are present in Chromium. If you're referring to the recent fiasco about cast not working in Chromium, that was a bug in M54. And guess what, it wasn't working in Chrome either!

I'd encourage you to read this document[3] detailing the differences between Chrome and Chromium instead of speculating.

[1] https://www.chromium.org/developers/design-documents/sync [2] https://codereview.chromium.org/2347503002 [3] https://chromium.googlesource.com/chromium/src/+/master/docs...