[LayoutNG] Delay layout of floats until fragmentation is known.
There a quite a few related changes in this patch:
- Renames NGFloatingObject -> NGUnpositionedFloat.
- Additionally remove some additional fields now that we have the node.
- Delays the layout of a same writing mode fragment until after we have
positioned it.
- Float which are in different writing modes have layout performed on them
eagerly as they don't need to wait for their position to know their fragmentation
offset.
BUG=635619
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Review-Url: https://codereview.chromium.org/2867243004
Cr-Commit-Position: refs/heads/master@{#472623}
39 files changed
