Sebastien, could you take a look or re-assign more appropriate person?

Findit suspects your CL 569094 with 89% confidence
https://chromium.googlesource.com/chromium/src/+/448f72d0803a96e428ea00f475d36b057758d3e4

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/068eac045cb65be73a109b03e7e28ce65cddf2ea

commit 068eac045cb65be73a109b03e7e28ce65cddf2ea
Author: Hitoshi Yoshida <peria@chromium.org>
Date: Thu Jun 21 08:27:13 2018

Revert "Add the about flags for the TabManager/RC features."

This reverts commit 448f72d0803a96e428ea00f475d36b057758d3e4.

Reason for revert: This CL may trigger sizes failing on chromium/Mac, and the failure prevents builds on Mac. So let me try to revert this.

Bug:  854896 

Original change's description:
> Add the about flags for the TabManager/RC features.
> 
> Change-Id: Id68cad067bb35f3b11bd8828806860110e8aaf79
> Reviewed-on: https://chromium-review.googlesource.com/1103304
> Commit-Queue: Sébastien Marchand <sebmarchand@chromium.org>
> Reviewed-by: François Doray <fdoray@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#569094}

TBR=chrisha@chromium.org,fdoray@chromium.org,sebmarchand@chromium.org

Change-Id: I3aa871436e096af1fb4583634b338a139d32c31f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/1109321
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569190}
[modify] https://crrev.com/068eac045cb65be73a109b03e7e28ce65cddf2ea/chrome/browser/about_flags.cc
[modify] https://crrev.com/068eac045cb65be73a109b03e7e28ce65cddf2ea/chrome/browser/flag_descriptions.cc
[modify] https://crrev.com/068eac045cb65be73a109b03e7e28ce65cddf2ea/chrome/browser/flag_descriptions.h
[modify] https://crrev.com/068eac045cb65be73a109b03e7e28ce65cddf2ea/tools/metrics/histograms/enums.xml

#2 cleared the tree, so removing this from the sheriff's queue

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d33f7dcbd7667f27a45182825b0882a97d96d913

commit d33f7dcbd7667f27a45182825b0882a97d96d913
Author: Sebastien Marchand <sebmarchand@chromium.org>
Date: Fri Jun 22 22:07:06 2018

Reland "Add the about flags for the TabManager/RC features."

This is a reland of 448f72d0803a96e428ea00f475d36b057758d3e4 with a fix
to remove a static initializer, the problem was that a global variable
was initialized using a member field of another global struct.

Bug:  854896 

Original change's description:
> Add the about flags for the TabManager/RC features.
>
> Change-Id: Id68cad067bb35f3b11bd8828806860110e8aaf79
> Reviewed-on: https://chromium-review.googlesource.com/1103304
> Commit-Queue: Sébastien Marchand <sebmarchand@chromium.org>
> Reviewed-by: François Doray <fdoray@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#569094}

Change-Id: I1b490e126b4a4359ba6314f0e2ccc1b631cd2143
Reviewed-on: https://chromium-review.googlesource.com/1110157
Commit-Queue: Sébastien Marchand <sebmarchand@chromium.org>
Commit-Queue: François Doray <fdoray@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569803}
[modify] https://crrev.com/d33f7dcbd7667f27a45182825b0882a97d96d913/chrome/browser/about_flags.cc
[modify] https://crrev.com/d33f7dcbd7667f27a45182825b0882a97d96d913/chrome/browser/flag_descriptions.cc
[modify] https://crrev.com/d33f7dcbd7667f27a45182825b0882a97d96d913/chrome/browser/flag_descriptions.h
[modify] https://crrev.com/d33f7dcbd7667f27a45182825b0882a97d96d913/chrome/browser/resource_coordinator/tab_manager_features.cc
[modify] https://crrev.com/d33f7dcbd7667f27a45182825b0882a97d96d913/chrome/browser/resource_coordinator/tab_manager_features.h
[modify] https://crrev.com/d33f7dcbd7667f27a45182825b0882a97d96d913/tools/metrics/histograms/enums.xml