Needs Detach on shadow root creation for v0 as well.

We don't DetachLayoutTree outside of the flat tree. Adding a shadow root
makes host children no longer part of the flat tree. At least not until
we add slots to the shadow tree. We already did this for v1 roots. It is
necessary for v0 roots as well.

Bug: 955861, 954826
Change-Id: I4de06ae5067297476a1c0a3a91d56696d71b4c86
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1581972
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653938}
2 files changed