I am confused. Isn't WASM supposed to be eventually AOTed (Ahead of Time Compile) or a least JITed? Why this bizarre twist with WASM-C-NATIVE? Browser should do just that instead of these dances around.
This isn't for running WASM from the web. This has nothing whatsoever to do with the WASM JIT that's in Spidermonkey. This is sandboxing for internal components of the browser (or any application really). But, this is a kind of AOT compilation involving WASM in the middle.