Bug
1541846 - Ensure namespace-aware “clear the stack” handling r=smaug
This change ensures that for all cases with spec requirements in the
form “clear the stack back to a foo context” — which involves checking
for elements with particular names — we only look for elements in the
HTML namespace, rather than additionally looking for elements which
aren’t in the HTML namespace but that also have those particular names.
Otherwise, without this change, we aren’t in conformance with the spec
requirements, and we fail several cases in the html5lib-tests suite.
Fixes https://github.com/validator/htmlparser/issues/33
Differential Revision: https://phabricator.services.mozilla.com/
D122722