Bug 1690607 [wpt PR 27461] - Portals: focus() inside portal should ch…

…ange active element, a=testonly

Automatic update from web-platform-tests
Portals: focus() inside portal should change active element

Allows a portal document's activeElement to update when focus is called.
Note that focus events won't be dispatched as the portal doesn't get
page focus, and the portal WebContents isn't set as the focused
WebContents (with the exception of orphaned portals). Updating the
activeElement also means an autofocused element inside a portal will
receive focus when the portal is activated.

More discussion here: WICG/portals#257

Change-Id: If67be1f424114653983b473a80c515337d49596a
Bug: 1059404
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2566072
Commit-Queue: Adithya Srinivasan <adithyaschromium.org>
Reviewed-by: Lucas Gadani <lfgchromium.org>
Reviewed-by: Jeremy Roman <jbromanchromium.org>
Reviewed-by: Alex Moshchuk <alexmoschromium.org>
Reviewed-by: David Trainor <dtrainorchromium.org>
Cr-Commit-Position: refs/heads/master{#853647}

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wpt-commits: a507854e826d126010758ba44847d1b67fb29c01
wpt-pr: 27461

UltraBlame original commit: 7e6160586f3c29315b5b2267b293ecbdfefd4324