The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cb6c4c2d4252cce1ea596b03a7aaee1a9bd469c1

commit cb6c4c2d4252cce1ea596b03a7aaee1a9bd469c1
Author: Xida Chen <xidachen@chromium.org>
Date: Thu Aug 16 15:27:46 2018

Disable TabManagerTest.ProactiveFastShutdownWithBeforeunloadHandler

TBR=wjmaclean@chromium.org
NOTRY=true

Bug:  874915 
Change-Id: Id0fae86ef2e130185d92ad28383c74036dcd96f3
Reviewed-on: https://chromium-review.googlesource.com/1177881
Reviewed-by: Xida Chen <xidachen@chromium.org>
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583660}
[modify] https://crrev.com/cb6c4c2d4252cce1ea596b03a7aaee1a9bd469c1/chrome/browser/resource_coordinator/tab_manager_browsertest.cc

According to FindIt in  issue 874958 , The most likley culprit is https://chromium-review.googlesource.com/q/I47147cd5f33ea44079c0a319626c57f3c5813af8

rdevlin.cronin@ and fmeawad@: Can you help find the reason? 

Analysis: https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVywQELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCKKAWNocm9taXVtLmNocm9taXVtb3MvbGludXgtY2hyb21lb3MtZGJnLzczMjcvYnJvd3Nlcl90ZXN0cy9WR0ZpVFdGdVlXZGxjbFJsYzNRdVVISnZZV04wYVhabFJtRnpkRk5vZFhSa2IzZHVWMmwwYUVKbFptOXlaWFZ1Ykc5aFpFaGhibVJzWlhJPQwLEhNNYXN0ZXJGbGFrZUFuYWx5c2lzGAEM

Hmm... I'd be rather surprised if https://chromium-review.googlesource.com/q/I47147cd5f33ea44079c0a319626c57f3c5813af8 is the culprit - it doesn't really touch tab management code, and I'd expect if it were the cause, we'd see a more catastrophic error.

But, easy way to check - I'll revert and see if the flakiness goes away.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ba93775280ece82d6bcc20c7adb7240465686294

commit ba93775280ece82d6bcc20c7adb7240465686294
Author: Devlin <rdevlin.cronin@chromium.org>
Date: Fri Aug 17 21:37:59 2018

Revert "Disable TabManagerTest.ProactiveFastShutdownWithBeforeunloadHandler"

This reverts commit cb6c4c2d4252cce1ea596b03a7aaee1a9bd469c1.

Reason for revert: Reverted suspected culprit; checking to see if still flaky.

Original change's description:
> Disable TabManagerTest.ProactiveFastShutdownWithBeforeunloadHandler
> 
> TBR=wjmaclean@chromium.org
> NOTRY=true
> 
> Bug:  874915 
> Change-Id: Id0fae86ef2e130185d92ad28383c74036dcd96f3
> Reviewed-on: https://chromium-review.googlesource.com/1177881
> Reviewed-by: Xida Chen <xidachen@chromium.org>
> Reviewed-by: James MacLean <wjmaclean@chromium.org>
> Commit-Queue: Xida Chen <xidachen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#583660}

TBR=xidachen@chromium.org,wjmaclean@chromium.org

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

Bug:  874915 
Change-Id: Ie5e977ce5893b35b7510e19c330b668ee6ff52f0
Reviewed-on: https://chromium-review.googlesource.com/1179348
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584202}
[modify] https://crrev.com/ba93775280ece82d6bcc20c7adb7240465686294/chrome/browser/resource_coordinator/tab_manager_browsertest.cc

The NextAction date has arrived: 2018-08-20

Tests still flaky after the revert:

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests%20%28dbg%29%281%29%2832%29/52198

Thus, relanding revision f41f215c837b6b9f4f7db402a78638bf7a0b2676 and re-disabling the test.

fdoray@, looks like you've worked on this test in the past - mind taking a look?

We think the source of the flakiness is actually buried deep in the bowels of RenderProcessHost and Mojo, as outlined here:

https://docs.google.com/document/d/1pu-VjoQiPK4w7N04-bMBBKODnqZGb4QHZNuoYgzMU9A/edit#

Also marking this as a dup of bug 874851.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e3fd7864cb3e113283190db1277d3f4433c54805

commit e3fd7864cb3e113283190db1277d3f4433c54805
Author: Devlin Cronin <rdevlin.cronin@chromium.org>
Date: Mon Aug 20 15:21:09 2018

Reland "Disable TabManagerTest.ProactiveFastShutdownWithBeforeunloadHandler"

Test is still flaky.

Original change's description:
> Disable TabManagerTest.ProactiveFastShutdownWithBeforeunloadHandler
>
> TBR=wjmaclean@chromium.org
> NOTRY=true
>
> Bug:  874915 
> Change-Id: Id0fae86ef2e130185d92ad28383c74036dcd96f3
> Reviewed-on: https://chromium-review.googlesource.com/1177881
> Reviewed-by: Xida Chen <xidachen@chromium.org>
> Reviewed-by: James MacLean <wjmaclean@chromium.org>
> Commit-Queue: Xida Chen <xidachen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#583660}

TBR=xidachen@chromium.org,wjmaclean@chromium.org

Bug:  874915 
Change-Id: I75d5ca813702dace0d3966baac2bd69d517dd1c8
Reviewed-on: https://chromium-review.googlesource.com/1181164
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584450}
[modify] https://crrev.com/e3fd7864cb3e113283190db1277d3f4433c54805/chrome/browser/resource_coordinator/tab_manager_browsertest.cc