The html-id attribute is an internal one used by WTR to get the accessible of an element by its id. The toolkit attribute will make the results different for every platform.
Created attachment 448731 [details]
I don't know why EWS is taking the old expectation for accessibility/content-editable-as-textarea.html. The new one is included in the patch and the old one removed.
Committed r287833 (245885@trunk): <https://commits.webkit.org/245885@trunk>