Just for the record, the Wasm implementation in Chrome is a subsystem of V8. It's integrated into the main codebase and shares a lot of runtime services with the JavaScript support, primarily the optimizing compiler tier. So improvements to the (backend) of the optimizing compiler in V8 benefit both JavaScript and Wasm. There is also a baseline JIT compiler which is specifically built solely for faster Wasm startup and not used by JS.

The team (my former team) that maintains Wasm is a subteam of V8 and they all work together. This is unlike (P)NaCl which was both a separate team and a separate subsystem within Chrome. All of the former NaCl people work on Wasm now, primarily tooling and standards.