I found this while investigating the failures bug 1740089 caused. Probably also fixes bug 1737131.

This I noticed while working on the following patches. Shouldn't have
any behavior change: the behavior does in fact match the element state
flag semantics correctly if we do this. We did split the dir flags into
two element bits a while ago.

:not(:dir()) still behaves correctly of course, and we have tests for that.

Use the same document state mechanism we have for :moz-locale-dir. Also,
simplify the setup of the later to be the same as :dir(), allowing the
matching code to be less repetitive.

This should fix some flakiness in chrome mochitests, but we have no existing
tests for these pseudo-classes more generally and since they're just
chrome-only I'm not super-excited about adding more.

Depends on D130734

Behind a pref for now. Given these selectors do nothing on non-chrome
documents (they just don't match) it seems worth trying.

A cursory search seems to indicate they're not used for UA detection or
something like that (or at least I haven't found such an usage).

Depends on D130735

And remove code for :-moz-submit-invalid completely.

Depends on D130736

Without this some tests fail with the previous patch because code like:

https://searchfox.org/mozilla-central/rev/267682a8f45221bf0bfe999d4a0239706a43bc56/browser/base/content/browser-gestureSupport.js#651

starts throwing. Unfortunately I had missed that on my try run, because
the error message didn't include that exception (it seemed like an
intermittent browser-chrome failure instead).

We could expose a ChromeOnly API for this, but this seems better. This
fixes it trivially, and also removes the "no url data" situation from
the selector parser, which is nice.

Backed out for causing build bustages.

Backout link: https://hg.mozilla.org/integration/autoland/rev/248823d9b8df67f62f2b126a463bfa01c7c0b9c5

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=ba8e644ee9d2caa065fc18dd92a603c865df2d17&selectedTaskRun=LD48LT6oS7CTT7EVJXtcVA.0

Failure log:

bustage - https://treeherder.mozilla.org/logviewer?job_id=357576885&repo=autoland&lineNumber=40070
failures before the patch - https://treeherder.mozilla.org/logviewer?job_id=357577922&repo=autoland&lineNumber=6210
- https://treeherder.mozilla.org/logviewer?job_id=357575845&repo=autoland&lineNumber=86847

The last 2 patches were backed out, but the first 2 were merged to central:
https://hg.mozilla.org/mozilla-central/rev/4176f472e85a
https://hg.mozilla.org/mozilla-central/rev/e76b53d685ee

https://hg.mozilla.org/mozilla-central/rev/09cdd8f9b238
https://hg.mozilla.org/mozilla-central/rev/6a6251c65131
https://hg.mozilla.org/mozilla-central/rev/67a281174487