Amazon Web Services was explicitly listed in the group of companies at the bottom that did not get notification.

It was a day after disclosure our ELBs were patched.

Yes, and I am worried they did not get that notification

How Chromium did not get prior word from Google?

Chromium should not have been vulnerable to the bug, since it does not use openssl (last i looked, it used NSS).

Given that Adam Langley works with the chrome folks, i suspect it did not end up needing it in the end :)

I suspect, given the email gave no details, they had no knowledge of whether it was the same bug or not.

That seems like a Facebook internal issue. No reason why they can't be expected to share info with entities that they own.