HTMLImageElement.decoding should reflect the decoding content attribute, limited to only known values. We are currently missing the *limited to only known values* logic:
Created attachment 433803 [details]
Created attachment 433820 [details]
Committed r280047 (239782@main): <https://commits.webkit.org/239782@main>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 433820 [details].