similar to <https://webkit.org/b/221594> ([iOS] Add support for the language/subtitle tracks button using `UIMenu`)
<rdar://problem/75462340>
Created attachment 423297 [details] Patch
Comment on attachment 423297 [details] Patch rs=me once the bots are happy
Created attachment 423367 [details] Patch
Created attachment 423383 [details] Patch
Created attachment 423395 [details] Patch
Committed r274521: <https://commits.webkit.org/r274521> All reviewed patches have been landed. Closing bug and clearing flags on attachment 423395 [details].