1849107 - Ensure scripts moving between documents between script running steps are correctly handled

Status: NEW

(Core :: DOM: Core & HTML, task)

Description

[Henri Sivonen (:hsivonen)]

Back in 2010 the HTML spec required scripts to run even if they were moved between documents between various steps of script parsing, preparation, and execution. These days, all three docs must be the same (or the document associated with the parser must be null for scripts that aren't parser-inserted).

Currently, we perform the check that parsing and preparation match but the later check is more ad hoc. We should re-do this code properly and re-assess the use of a weak reference to the parser.