[LayoutNG] Remove adding out-of-flow children within PositionLeadingItems.

Now that we don't early exit if we are an empty linebox we can just rely
on the regular out-of-flow children adding pass.

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I397a64e6d1df293d03c317dbfdf1f63a38f54206
Bug: 635619
Reviewed-on: https://chromium-review.googlesource.com/1126681
Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572714}
1 file changed