[LayoutNG] Anonymous blocks percentage size fix

Anonymous blocks were passing indefinite block percentage resolution size to
their children. The fix is to handle anonymous blocks like we do anonymous
fragments, and use ParentPercentageResolutionSize().

Bug: 635619
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I147e92570a60b84aa0b840201542d98c0517e82e
Reviewed-on: https://chromium-review.googlesource.com/1034094
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Commit-Queue: Aleks Totic <atotic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554745}
5 files changed