+++ This bug was initially created as a clone of Bug #1555633 +++
+++ This bug was initially created as a clone of Bug #1550945 +++

In bug 1536744, M-C removed nsIProtocolHandler.newURI and hard-coded all schemes in the system here:
https://searchfox.org/mozilla-central/rev/c0ca77697c6868482f30af873ec8069f2c080a34/netwerk/base/nsNetUtil.cpp#1707

We followed with
https://searchfox.org/comm-central/source/mailnews/base/util/nsNewMailnewsURI.cpp

So while bug 1550945 fixed the bustage, there is scope for some clean-up:

1. Maybe fix the hard-coded include paths at the top of the file
2. Make sure JS Account is adequately catered for (done in bug 1555633)
3. Consider removing some "simple" URL implementations, see bug 1550945 comment #0, quote: "remove some of the implementations".

... assuming this was what you were looking for for part 1?

Try run: https://treeherder.mozilla.org/#/jobs?repo=try-comm-central&revision=3720363e46d95dc6598028e98fff3bbd9794f2fd

I guess so, but part 3 is more interesting.