Check LayoutView parent for top layer siblings.

The check for the need for re-attachment would no longer work with the
current patch in [1]. Instead check if the sibling LayoutObject
candidate is in the top layer (LayoutView child) already, in which case
we can use it as a sibling. If the candidate needs re-attaching, it will
be removed and re-inserted in the correct place.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/1323555

TEST=html/dialog

Bug: 914784
Change-Id: I5df489382fb95ca6de8c5ea25d0270206f2fbe4a
Reviewed-on: https://chromium-review.googlesource.com/c/1400698
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620795}
1 file changed