drawCustomFocusRing has been removed from the spec: https://html5.org/r/8854 Removed in Blink as well: https://codereview.chromium.org/289283019/

If this is just code deletion, it would probably be an easy mentored bug. gw280, want to mentor this?

This was implemented in bug 540456.

This feature was removed from the spec years ago. Support from it was removed from other browsers then too. We never pref'd it on either. The original implementer of the feature is also long gone. It was also suggested years ago that we remove this. The tests are already skipped on most platforms except Linux. Let's just nuke this from orbit already so we can resolve the intermittent in bug 1005846 from these obsolete tests.

Comment on attachment 9028033 [details] [diff] [review] remove obsolete drawCustomFocusRing from Canvas2D r=me on the webidl change, since the functionality is behind a default-off pref.

Pushed by lsalzman@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/125f1466fe9d remove obsolete drawCustomFocusRing from Canvas2D. r=jrmuizel, r=bholley

(Removing site-compat keyword as Firefox has never enabled this by default as per Comment 3.)

This was never enabled in Fx, and isn't mentioned on MDN anywhere (AFAICS), so I'm removing the dev-doc-needed keyword. Nothing to see here folks, move along.