You can easily write an extension to in-browser Dev Tools to show human-friendly representation of any binary protocol for development/debugging purpose.

Nice. Are you aware of any Chrome extension for decoding Flash's 'application/x-amf' Action Message Format like Burp, Charles, and this Firefox extension do?

https://addons.mozilla.org/en-US/firefox/addon/amf-explorer/

Nope, sorry! But Firefox addons will be soon switching to extension format compatible with Chrome, so you might get it for “free.”