The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b71ac55bffca1c376d6ed4e540194436daccfbd1

commit b71ac55bffca1c376d6ed4e540194436daccfbd1
Author: Morten Stenshorne <mstensho@opera.com>
Date: Fri Aug 25 16:35:23 2017

Locate the correct flow thread for spanners and out-of-flow objects.

LayoutFlowThread::LocateFlowThreadContainingBlockOf() used to just
give up if the nearest ancestor flow thread of some object wasn't the
containing flow thread.

The machinery that maintains the special-objects
(LayoutMultiColumnSet, LayoutMulticolumnSpannerPlaceholder) for
multicol still needs to ignore out-of-flow objects and spanners,
though, so I moved the check for this from
LocateFlowThreadContainingBlockOf() to
FlowThreadDescendantWasInserted() and
FlowThreadDescendantWillBeRemoved().

Checking on the paint side whether page logical height is known is
no longer necessary.

Bug: 757947
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ief0492e9de52b01b08c3bc0318cb3c8abe67ccd3
Reviewed-on: https://chromium-review.googlesource.com/632057
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@opera.com>
Cr-Commit-Position: refs/heads/master@{#497437}
[modify] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-features=LayoutNG
[modify] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/LayoutTests/FlagExpectations/enable-slimming-paint-v2
[add] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/LayoutTests/fast/multicol/out-of-flow/nested-with-abspos-inside-relpos-expected.html
[add] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/LayoutTests/fast/multicol/out-of-flow/nested-with-abspos-inside-relpos.html
[modify] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/Source/core/layout/LayoutFlowThread.cpp
[modify] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/Source/core/layout/LayoutMultiColumnFlowThread.cpp
[modify] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/Source/core/layout/LayoutMultiColumnFlowThread.h
[modify] https://crrev.com/b71ac55bffca1c376d6ed4e540194436daccfbd1/third_party/WebKit/Source/core/paint/TableSectionPainter.cpp

Reverting the fix, since it caused too much trouble. Probably fixable, but I don't have time for that now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/47d61290f9f82f13f775bd43e57e6437e7638512

commit 47d61290f9f82f13f775bd43e57e6437e7638512
Author: Morten Stenshorne <mstensho@opera.com>
Date: Mon Aug 28 17:40:47 2017

Revert "Locate the correct flow thread for spanners and out-of-flow objects."

This reverts commit b71ac55bffca1c376d6ed4e540194436daccfbd1.

Reason for revert: Opened up a can of worms. Re-seal it.

Original change's description:
> Locate the correct flow thread for spanners and out-of-flow objects.
> 
> LayoutFlowThread::LocateFlowThreadContainingBlockOf() used to just
> give up if the nearest ancestor flow thread of some object wasn't the
> containing flow thread.
> 
> The machinery that maintains the special-objects
> (LayoutMultiColumnSet, LayoutMulticolumnSpannerPlaceholder) for
> multicol still needs to ignore out-of-flow objects and spanners,
> though, so I moved the check for this from
> LocateFlowThreadContainingBlockOf() to
> FlowThreadDescendantWasInserted() and
> FlowThreadDescendantWillBeRemoved().
> 
> Checking on the paint side whether page logical height is known is
> no longer necessary.
> 
> Bug: 757947
> Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
> Change-Id: Ief0492e9de52b01b08c3bc0318cb3c8abe67ccd3
> Reviewed-on: https://chromium-review.googlesource.com/632057
> Reviewed-by: Emil A Eklund <eae@chromium.org>
> Commit-Queue: Morten Stenshorne <mstensho@opera.com>
> Cr-Commit-Position: refs/heads/master@{#497437}

TBR=mstensho@opera.com,robhogan@gmail.com,eae@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 757947
Change-Id: Idf54d6cea2c03871c3a3443880f6b5b331cd7d30
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Reviewed-on: https://chromium-review.googlesource.com/637870
Reviewed-by: Morten Stenshorne <mstensho@opera.com>
Commit-Queue: Morten Stenshorne <mstensho@opera.com>
Cr-Commit-Position: refs/heads/master@{#497791}
[modify] https://crrev.com/47d61290f9f82f13f775bd43e57e6437e7638512/third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-features=LayoutNG
[modify] https://crrev.com/47d61290f9f82f13f775bd43e57e6437e7638512/third_party/WebKit/LayoutTests/FlagExpectations/enable-slimming-paint-v2
[delete] https://crrev.com/b92fa52719c8826a96d85e19f0b204c76998f523/third_party/WebKit/LayoutTests/fast/multicol/out-of-flow/nested-with-abspos-inside-relpos-expected.html
[delete] https://crrev.com/b92fa52719c8826a96d85e19f0b204c76998f523/third_party/WebKit/LayoutTests/fast/multicol/out-of-flow/nested-with-abspos-inside-relpos.html
[modify] https://crrev.com/47d61290f9f82f13f775bd43e57e6437e7638512/third_party/WebKit/Source/core/layout/LayoutFlowThread.cpp
[modify] https://crrev.com/47d61290f9f82f13f775bd43e57e6437e7638512/third_party/WebKit/Source/core/layout/LayoutMultiColumnFlowThread.cpp
[modify] https://crrev.com/47d61290f9f82f13f775bd43e57e6437e7638512/third_party/WebKit/Source/core/layout/LayoutMultiColumnFlowThread.h
[modify] https://crrev.com/47d61290f9f82f13f775bd43e57e6437e7638512/third_party/WebKit/Source/core/paint/TableSectionPainter.cpp

Reverted, because it caused  bug 759338 .

The assigned owner "mstensho@opera.com" is not able to receive e-mails, please re-triage.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot