e-onkyo is a commonly referenced high-resolution music downloads store for the Japanese market; it mostly focuses on domestic Japanese releases, but also hosts a fair amount of releases from other markets as well. Rudimentary "purchase for download" autoselection was added for this store (among a couple of others) back in MBS-7924, but no validation was added at the time. OTOTOY validation was added in MBS-13415, so it seems like a good idea to continue cleaning up after MBS-7924 by adding validation for e-onkyo as well. In addition, given what seems to be relatively common reference to this store by editors working with Japanese releases, it seems worthwhile to sidebar it like mora, レコチョク, and OTOTOY.