[LayoutNG] Pass Container() to NGOutOfFlowLayout instead of ContainerBlock()

Fixes external/wpt/css/css-position/position-relative-* DCHECK crashes

Had to modify NGOutOfFlowLayoutPart constructor.

It used to take NGBlockNode to compute scrollbar sizes,
contains_absolute, and contains_fixed.

Containing block can be arbitrary LayoutBoxModelObject with inline blocks.
None of NG*Nodes can be constructed from LayoutBoxModelObject.
=> NGOutOfFlowLayoutPart constructor cannot take NG*Node, but must take
all required LayoutObject properties instead.

Bug: 740993
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I731800feddf5d53a9104f62d9d616f56a6195671
Reviewed-on: https://chromium-review.googlesource.com/845499
Commit-Queue: Aleks Totic <atotic@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526328}
7 files changed