The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/442328dea93402f53cc0c015d9eac254aa80cb2e

commit 442328dea93402f53cc0c015d9eac254aa80cb2e
Author: Robert Hogan <robhogan@gmail.com>
Date: Wed Jan 03 00:45:18 2018

[LayoutNG] Don't combine exclusions on a node if its desendants have some

If the descendants of an opportunity tree node have exclusions they will
get lost when combining the node's current exclusions, so avoid doing that.

Bug: 798436
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I90cde607c99fcfc808c1dafc531445bc25774cca
Reviewed-on: https://chromium-review.googlesource.com/847595
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526554}
[modify] https://crrev.com/442328dea93402f53cc0c015d9eac254aa80cb2e/third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-features=LayoutNG
[modify] https://crrev.com/442328dea93402f53cc0c015d9eac254aa80cb2e/third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_iterator.cc