Interesting. It appears the Windows DBG builds are unusually slow at running this test.

It's also possible that the test is legitimately failing, but that seems less likely.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d6a4dc08db43e75268e19da1376efbcb8ea80b21

commit d6a4dc08db43e75268e19da1376efbcb8ea80b21
Author: Makoto Shimazu <shimazu@chromium.org>
Date: Tue Aug 08 07:16:43 2017

Disabled flaky WebSocketBrowserTest.SSLConnectionLimit on win

WebSocketBrowserTest.SSLConnectionLimit is flaky on chromium.win. This patch
disables the test on OS_WIN.

TBR=ricea@chromium.org,mmenke@chromium.org

Bug:  753261 
Change-Id: If2bcdbb22a78ccdef60dbd38c1db1e973d050bc5
Reviewed-on: https://chromium-review.googlesource.com/604771
Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Makoto Shimazu <shimazu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492562}
[modify] https://crrev.com/d6a4dc08db43e75268e19da1376efbcb8ea80b21/chrome/browser/net/websocket_browsertest.cc

Test has been disabled, so removed the sheriff label.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/73956293a5a2368ac1c8fa9fd963eb75bca7a5a3

commit 73956293a5a2368ac1c8fa9fd963eb75bca7a5a3
Author: Adam Rice <ricea@chromium.org>
Date: Tue Aug 08 12:26:20 2017

Up timeout for WebSocketBrowserTest.SSLConnectionLimit

WebSocketBrowserTest.SSLConnectionLimit was timing out on Windows debug
bots. It has an internal timeout so that if it gets stuck it can report
how far it got. However, with the old timeout of 11 seconds it was often
only getting to around 190 sockets connected on the Windows debug bots.

The new timeout is 22 seconds which should give it plenty of time to
complete.

Also revert d6a4dc08db43e75268e19da1376efbcb8ea80b21 which disabled
the test on Windows.

BUG= 753261 

Change-Id: Ifbf0399967b6edf811698832ef07138461a0732b
Reviewed-on: https://chromium-review.googlesource.com/604636
Commit-Queue: Adam Rice <ricea@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Takeshi Yoshino <tyoshino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492602}
[modify] https://crrev.com/73956293a5a2368ac1c8fa9fd963eb75bca7a5a3/chrome/browser/net/websocket_browsertest.cc
[modify] https://crrev.com/73956293a5a2368ac1c8fa9fd963eb75bca7a5a3/net/data/websocket/multiple-connections.html

The problem with the slowness of Windows DBG builds is solved.

I'm seeing a few cases of it failing with ERR_NETWORK_CHANGED on Win7, but that must be some weirdness of the bots rather than anything to do with the test itself. It recovered on retry in all cases.