First failure here:
https://uberchromegw.corp.google.com/i/chromium.android/builders/Android%20Cronet%20Marshmallow%2064bit%20Perf/builds/10436

Error message looks like:

C 1136.988s Main  [FAIL] HTTPSFallbackTest.TLSv1_3InterferenceDisableVersion:
C 1136.988s Main  [ RUN      ] HTTPSCRLSetTest.ExpiredCRLSet
C 1136.988s Main  [ERROR:spawner_communicator.cc(225)] request failed, error: net::ERR_CONNECTION_REFUSED
C 1136.988s Main  ../../net/url_request/url_request_unittest.cc:10272: Failure
C 1136.988s Main  Value of: test_server.Start()
C 1136.988s Main    Actual: false
C 1136.988s Main  Expected: true
C 1136.988s Main  [ERROR:spawner_communicator.cc(225)] request failed, error: net::ERR_CONNECTION_REFUSED
C 1136.988s Main  [ERROR:remote_test_server.cc(130)] Failed stopping RemoteTestServer
C 1136.988s Main  ../../net/url_request/url_request_unittest.cc:10294: Failure
C 1136.988s Main  Expected: DoConnectionWithDelegate(ssl_options, &d, &ssl_info) doesn't generate new fatal failures in the current thread.
C 1136.988s Main    Actual: it does.
C 1136.988s Main  [  FAILED  ] HTTPSCRLSetTest.ExpiredCRLSet (16 ms)


Only commit in blamelist that touches net/ is: d15b34fd6a7c4775c6488fef1a4b7abd7f1c46e5
Update test server spawner to run multiple test servers in parallel

The spawner server quits with the following error. Will have a fix in a minute.

127.0.0.1 - - [29/Aug/2017 09:19:33] "POST /start HTTP/1.1" 200 -
I  858.902s Thread-1  Test server is running on port: 52858.
Traceback (most recent call last):
  File "/usr/lib/python2.7/SocketServer.py", line 295, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/usr/lib/python2.7/SocketServer.py", line 321, in process_request
    self.finish_request(request, client_address)
  File "/usr/lib/python2.7/SocketServer.py", line 334, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/lib/python2.7/SocketServer.py", line 649, in __init__
    self.handle()
  File "/usr/lib/python2.7/BaseHTTPServer.py", line 340, in handle
    self.handle_one_request()
  File "/usr/lib/python2.7/BaseHTTPServer.py", line 328, in handle_one_request
    method()
  File "/b/build/slave/Android_Cronet_Marshmallow_64bit_Perf/build/src/build/util/lib/common/chrome_test_server_spawner.py", line 381, in do_POST
    self._StartTestServer()
  File "/b/build/slave/Android_Cronet_Marshmallow_64bit_Perf/build/src/build/util/lib/common/chrome_test_server_spawner.py", line 339, in _StartTestServer
    assert not self.server.test_servers.has_key(port)
AttributeError: 'list' object has no attribute 'has_key'

https://chromium-review.googlesource.com/c/chromium/src/+/641073

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/309bd24c9dca914dfce162a336bc320cbd2e6af3

commit 309bd24c9dca914dfce162a336bc320cbd2e6af3
Author: Sergey Ulanov <sergeyu@google.com>
Date: Tue Aug 29 17:47:21 2017

Fix typo in chrome_test_server_spawner.py

SpawningServerRequestHandler.CleanupState() was setting test_servers to
[] instead of {}. As result test server spawner was crashing on some
bots.

TBR=jbudorick@chromium.org

Bug:  760196 
Change-Id: Ib11575bca5fad0d1f128e4673e6b50f4d9e58b9b
Reviewed-on: https://chromium-review.googlesource.com/641073
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#498160}
[modify] https://crrev.com/309bd24c9dca914dfce162a336bc320cbd2e6af3/build/util/lib/common/chrome_test_server_spawner.py

 Issue 760117  has been merged into this issue.

After the CL from comment #6, a different bot has similar-looking failures: https://build.chromium.org/p/chromium.android/builders/Android%20Cronet%20Lollipop%20Builder/builds/11434

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4b7dac4c9da04f73e80cf82bc2c33f7f8bcd35a2

commit 4b7dac4c9da04f73e80cf82bc2c33f7f8bcd35a2
Author: Tarun Bansal <tbansal@chromium.org>
Date: Tue Aug 29 19:57:28 2017

Speculatively revert "Fix typo in chrome_test_server_spawner.py"

This reverts commit 309bd24c9dca914dfce162a336bc320cbd2e6af3.

Reason for revert:
Breaks net unittests
See  crbug.com/760256 


Original change's description:
> Fix typo in chrome_test_server_spawner.py
> 
> SpawningServerRequestHandler.CleanupState() was setting test_servers to
> [] instead of {}. As result test server spawner was crashing on some
> bots.
> 
> TBR=jbudorick@chromium.org
> 
> Bug:  760196 
> Change-Id: Ib11575bca5fad0d1f128e4673e6b50f4d9e58b9b
> Reviewed-on: https://chromium-review.googlesource.com/641073
> Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#498160}

TBR=sergeyu@chromium.org,jbudorick@chromium.org

Change-Id: I3a807a1db148fe022ca1372b8d0624d08d4e449f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  760196 ,  760256 
Reviewed-on: https://chromium-review.googlesource.com/641353
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#498207}
[modify] https://crrev.com/4b7dac4c9da04f73e80cf82bc2c33f7f8bcd35a2/build/util/lib/common/chrome_test_server_spawner.py

 Issue 760256  has been merged into this issue.

Reverted the changed that caused the problem, https://chromium-review.googlesource.com/c/chromium/src/+/642150