I'll push the removed code to C-C now.

I'll see whether I can get the tests going.

Geoff, could you please take a look at the linting problems this introduced. And if you could get the test going, that would be a bonus.

Test already works:
https://taskcluster-artifacts.net/LvgPOcyFRcyIUcoiUXSuyA/0/public/logs/live_backing.log
TEST-PASS | comm/common/saxparser/test/unit/test_parser.js

Also the one we don't need since it's still in M-C worked:
TEST-PASS | comm/common/saxparser/test/unit/test_sanitizer.js

So all that's left is fixing the linting errors:
c:\mozilla-source\comm-central\comm\common\saxparser\test\unit.eslintrc.js
6:4 error Missing trailing comma. comma-dangle (eslint)

c:\mozilla-source\comm-central\comm\common\saxparser\test\unit\test_parser.js
24:20 error Unexpected named method 'startDocument'. func-names (eslint)
27:18 error Unexpected named method 'endDocument'. func-names (eslint)
etc.

I can of course put // eslint-disable-line func-names onto those.

Pushed by mozilla@jorgk.com:
https://hg.mozilla.org/comm-central/rev/715f97e4c9ae
Follow-up: Fix linting errors. rs=bustage-fix DONTBUILD

See also bug 1514666 and bug 1514669.