Able to reproduce the issue on Mac 10.11.5 using chrome version 54.0.2800.0.

Adding stable blocker as this is recent regression.

Thanks,

I'll look into this but I suspect that my patch only uncovered an underlying issue, perhaps relating to one of Stefan's changes.

Just to update, issue is still observed on MAC 10.11.5, Ubuntu 14.04 for chrome version 54.0.2808.0. 

@ cbiesinger: Gentle Ping.!, Request you to please provide an update on it as per your above comment. Please help us to reassign if this is not with respect to your change.

Thanks.!

If I disable PaintLayerScrollableArea::DelayScrollPositionClampScope (by commenting it out) this bug disappears, so this sounds a lot more like a scrolling bug.

(and of course, my change triggered this because we happened to overinvalidate things, so that covered it up)

szager@: Can we get an update on this issue.

Thank you!

This may be the same underlying issue as  bug 633212  which I'm now investigating as a flexbox bug

It looks like my patch for that bug does fix this one, too. Sorry Stefan!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e929360ccd93a1e98db3b19929a68d1ed4fa4d5d

commit e929360ccd93a1e98db3b19929a68d1ed4fa4d5d
Author: cbiesinger <cbiesinger@chromium.org>
Date: Fri Aug 05 19:17:26 2016

[css-flexbox] Have to use forceChildLayout to force layout

The flexbox code was assuming that calling layoutIfNeeded()
will do a full layout if needsLayout() is true.

However, that is not the case. It is possible for needsLayout()
to return true because posChildNeedsLayout is true, in which
case calling layout() will not do the full layout that the
flexbox code expects. Instead, call forceChildLayout to
ensure that layout happens.

R=eae@chromium.org,dgrogan@chromium.org
CC=szager@chromium.org
BUG= 633212 , 629491 

Review-Url: https://codereview.chromium.org/2219433002
Cr-Commit-Position: refs/heads/master@{#410135}

[add] https://crrev.com/e929360ccd93a1e98db3b19929a68d1ed4fa4d5d/third_party/WebKit/LayoutTests/css3/flexbox/bug633212.html
[modify] https://crrev.com/e929360ccd93a1e98db3b19929a68d1ed4fa4d5d/third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp

Are we planning a 52 point release? Might be nice to take this patch too. It seems this specific version of the bug does not reproduce on 52 but  bug 633212 's testcase does fail on 52, and the patch is very safe.

[Automated comment] Request affecting a post-stable build (M52), manual review required.

Your change meets the bar and is auto-approved for M53 (branch: 2785)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/92a2a1f5852a882ef9671a8d792313dc670ac899

commit 92a2a1f5852a882ef9671a8d792313dc670ac899
Author: Christian Biesinger <cbiesinger@chromium.org>
Date: Mon Aug 08 02:35:26 2016

[css-flexbox] Have to use forceChildLayout to force layout

The flexbox code was assuming that calling layoutIfNeeded()
will do a full layout if needsLayout() is true.

However, that is not the case. It is possible for needsLayout()
to return true because posChildNeedsLayout is true, in which
case calling layout() will not do the full layout that the
flexbox code expects. Instead, call forceChildLayout to
ensure that layout happens.

R=eae@chromium.org,dgrogan@chromium.org
CC=szager@chromium.org
BUG= 633212 , 629491 

Review-Url: https://codereview.chromium.org/2219433002
Cr-Commit-Position: refs/heads/master@{#410135}
(cherry picked from commit e929360ccd93a1e98db3b19929a68d1ed4fa4d5d)

Review URL: https://codereview.chromium.org/2224833002 .

Cr-Commit-Position: refs/branch-heads/2785@{#519}
Cr-Branched-From: 68623971be0cfc492a2cb0427d7f478e7b214c24-refs/heads/master@{#403382}

[add] https://crrev.com/92a2a1f5852a882ef9671a8d792313dc670ac899/third_party/WebKit/LayoutTests/css3/flexbox/bug633212.html
[modify] https://crrev.com/92a2a1f5852a882ef9671a8d792313dc670ac899/third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp

Re #10, as of now there is no M52 refresh release plan. But we can surely take this change in if we cut new M52 stable rc. Does that sound good?

Rechecked this on chrome version 54.0.2824.0 on Windows 7 and MAC 10.11.6, 54.0.2423.0 on Ubuntu 14.04. fix is working as intended.

Adding TE-Verified labels.

Thanks.!

Rechecked this on chrome version 53.0.2785.57.0 on Windows 7, Ubuntu 14.04 and MAC 10.11.6, fix is working as intended.

Adding TE-Verified labels.

Thanks.!

 Issue 623019  has been merged into this issue.