This is a testharness.js-based test.
PASS HTML parser must not instantiate custom elements inside template elements 
PASS HTML parser must not use the registry of the owner element's document inside an iframe 
PASS HTML parser must use the registry of the content document inside an iframe 
PASS HTML parser must not instantiate a custom element defined inside an frame in frame element's owner document 
PASS HTML parser must use the registry of window.document in a document created by document.implementation.createHTMLDocument() 
FAIL HTML parser must use the registry of window.document in a document created by document.implementation.createXHTMLDocument() assert_true: expected true got false
PASS HTML parser must use the registry of window.document in a document created by new Document 
PASS HTML parser must use the registry of window.document in a document created by XMLHttpRequest 
Harness: the test ran to completion.