Consume user activation when creating a new top-level traversable

[CanadaHonk]

Closes #10108.

• At least two implementers are interested (and none opposed):
  • Mozilla
  • Chromium (already implemented)
• Tests are written and can be reviewed and commented upon at:
  • HTML: Consume user activation for window.open (multi-global test) web-platform-tests/wpt#49138
  • https://bugzilla.mozilla.org/show_bug.cgi?id=1879820
• Implementation bugs are filed:
  • Chromium: Already has this behavior (afaik)
  • Gecko: https://bugzilla.mozilla.org/show_bug.cgi?id=1879820
  • WebKit: …
• MDN issue is filed: …
• The top of this comment includes a clear commit message to use.

(See WHATWG Working Mode: Changes for more details.)

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/document-sequences.html ( diff )

[zcorpan]

I think this looks reasonable. It will only consume when actually creating a top-level traversable.

[EdgarChen]

WPT tests will be added in https://bugzilla.mozilla.org/show_bug.cgi?id=1879820.

[annevk]

Thanks! @zcorpan can you complete OP?