+dmurph@, your CL has been identified as the culprit. Can you PTAL? It's pretty large, so I'd prefer not reverting it, and will just disable the test in the meantime, but I'll assign the bug to you to look into the cause.

Disabling CL here: https://chromium-review.googlesource.com/c/chromium/src/+/1261700

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/97ba6ddb3e711eff30910c3b5c63c6c07bfc806e

commit 97ba6ddb3e711eff30910c3b5c63c6c07bfc806e
Author: Martin Šrámek <msramek@chromium.org>
Date: Thu Oct 04 15:33:41 2018

Disable WebViewTest.Shim_testFindInMultipleWebViews on Windows

Due to flakiness.

TBR=ekaramad@chromium.org

Bug:  892085 
Change-Id: I96d8a3b14583c340abba18a725941b8ae0c1cf06
Reviewed-on: https://chromium-review.googlesource.com/c/1261700
Commit-Queue: Martin Šrámek <msramek@chromium.org>
Reviewed-by: Martin Šrámek <msramek@chromium.org>
Reviewed-by: Ehsan Karamad <ekaramad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596682}
[modify] https://crrev.com/97ba6ddb3e711eff30910c3b5c63c6c07bfc806e/chrome/browser/apps/guest_view/web_view_browsertest.cc

Note that this is only for network_service_browser_tests.

The strangest part here is that my change doesn't do any behavioral changes, it's all behind a flag.

The only behavioral change is how inspector agents are stored.

Removing Sheriff-Chromium as the test is disabled.

re-enabling to see if it is flaky still

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bce878b00ade8b4488ccd5ba990e05c9450bd4af

commit bce878b00ade8b4488ccd5ba990e05c9450bd4af
Author: Daniel Murphy <dmurph@chromium.org>
Date: Thu Jan 03 21:33:56 2019

Revert "Disable WebViewTest.Shim_testFindInMultipleWebViews on Windows"

This reverts commit 97ba6ddb3e711eff30910c3b5c63c6c07bfc806e.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Disable WebViewTest.Shim_testFindInMultipleWebViews on Windows
> 
> Due to flakiness.
> 
> TBR=ekaramad@chromium.org
> 
> Bug:  892085 
> Change-Id: I96d8a3b14583c340abba18a725941b8ae0c1cf06
> Reviewed-on: https://chromium-review.googlesource.com/c/1261700
> Commit-Queue: Martin Šrámek <msramek@chromium.org>
> Reviewed-by: Martin Šrámek <msramek@chromium.org>
> Reviewed-by: Ehsan Karamad <ekaramad@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#596682}

TBR=msramek@chromium.org,ekaramad@chromium.org

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

Bug:  892085 
Change-Id: I8b417d49cef605a3dd734886332ac70b1f53d8d7
Reviewed-on: https://chromium-review.googlesource.com/c/1394869
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Commit-Queue: Daniel Murphy <dmurph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619763}
[modify] https://crrev.com/bce878b00ade8b4488ccd5ba990e05c9450bd4af/chrome/browser/apps/guest_view/web_view_browsertest.cc

Let's close this if no reverts happen in two weeks.

The NextAction date has arrived: 2019-01-17