Earlier quoted context omitted.
By the time Google disables PNaCl on Chrome Apps, this kind of thing won't be an issue. There is a reason why the announced 2018 deactivation excluded Chrome Apps and Extensions.
I haven't seen any real activity from browser makers to add raw UDP APIs.
Well, for the Chrome Apps use case for Chrome OS, chrome.sockets.udp seems to be available, and wasm can call out to JS APIs. What other browser vendors do isn't really relevant for Chrome Apps.