Example failures:

https://ci.chromium.org/p/chromium/builders/luci.chromium.try/android-marshmallow-arm64-rel/74351
https://ci.chromium.org/p/chromium/builders/luci.chromium.try/android-marshmallow-arm64-rel/74957
https://ci.chromium.org/p/chromium/builders/luci.chromium.try/android-marshmallow-arm64-rel/75414

The symptom is that the browser seems to shut down abruptly:

  Traceback (most recent call last):
    _RunGpuTest at content/test/gpu/gpu_tests/gpu_integration_test.py:138
      self.RunActualGpuTest(url, *args)
    RunActualGpuTest at content/test/gpu/gpu_tests/context_lost_integration_test.py:102
      getattr(self, test_name)(test_path)
    _ContextLost_WebGLUnblockedAfterUserInitiatedReload at content/test/gpu/gpu_tests/context_lost_integration_test.py:312
      timeout=wait_timeout)
    traced_function at third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
      return func(*args, **kwargs)
    WaitForJavaScriptCondition at third_party/catapult/telemetry/telemetry/internal/browser/web_contents.py:239
      return self._inspector_backend.WaitForJavaScriptCondition(*args, **kwargs)
    traced_function at third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
      return func(*args, **kwargs)
    WaitForJavaScriptCondition at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py:288
      return py_utils.WaitFor(IsJavaScriptExpressionTrue, timeout)
    WaitFor at third_party/catapult/common/py_utils/py_utils/__init__.py:136
      res = condition()
    IsJavaScriptExpressionTrue at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py:285
      return self._EvaluateJavaScript(condition, context_id, timeout)
    traced_function at third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
      return func(*args, **kwargs)
    Inner at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py:37
      return func(inspector_backend, *args, **kwargs)
    _EvaluateJavaScript at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py:533
      self._runtime.Crash(context_id, timeout)
    Crash at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_runtime.py:81
      res = self._inspector_websocket.SyncRequest(request, timeout)
    SyncRequest at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py:127
      self._SendRequest(req)
    _SendRequest at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py:115
      self._socket.send(data)
    send at third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py:234
      return self.send_frame(frame)
    send_frame at third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py:259
      l = self._send(data)
    _send at third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py:423
      return send(self.sock, data)
    send at third_party/catapult/telemetry/third_party/websocket-client/websocket/_socket.py:113
      raise WebSocketConnectionClosedException("socket is already closed.")
  WebSocketConnectionClosedException: socket is already closed.
  
  Locals:
    data : '\x81\xa2\x8a|!\xdc\xf1^L\xb9\xfe\x14N\xb8\xa8F\x01\xfe\xda\x1dF\xb9\xa4\x1fS\xbd\xf9\x14\x03\xf0\xaa^H\xb8\xa8F\x01\xed\xb9\x01'
    sock : None


Unfortunately there is no stack trace which would indicate whether the browser crashed, or why.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/872e850f22987eaa8067e72b490c70580c8d528f

commit 872e850f22987eaa8067e72b490c70580c8d528f
Author: Oksana Zhuravlova <oksamyt@chromium.org>
Date: Fri Aug 31 18:27:12 2018

Mark a context_lost test flaky on Android

Reported in  https://crbug.com/879423 

Bug:  879423 

Change-Id: Ie9ef30aca2446873cdb271608234adef5ca96fe3
Reviewed-on: https://chromium-review.googlesource.com/1200182
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588096}
[modify] https://crrev.com/872e850f22987eaa8067e72b490c70580c8d528f/content/test/gpu/gpu_tests/context_lost_expectations.py

Hopefully the flaky expectation will let this test continue to at least run on Android. Won't be able to make further progress on this 

...unless we can get a stack trace from the crashing browser – if that's what's happening.

 Issue 895765  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9780253fa75f648aea3070fa2079e1f314d33f48

commit 9780253fa75f648aea3070fa2079e1f314d33f48
Author: Christos Froussios <cfroussios@chromium.org>
Date: Tue Oct 16 14:34:12 2018

Disable ContextLost_WebGLUnblockedAfterUserInitiatedReload

gpu_tests.context_lost_integration_test.ContextLostIntegrationTest.ContextLost_WebGLUnblockedAfterUserInitiatedReload in context_lost_tests
is flaky on Win10 Debug

TBR=kbr@chromium.org

Bug:  895765 ,  879423 
Change-Id: Ic36400494df68f257329e040be2c72f1ad2ec3a6
Reviewed-on: https://chromium-review.googlesource.com/c/1283049
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599973}
[modify] https://crrev.com/9780253fa75f648aea3070fa2079e1f314d33f48/content/test/gpu/gpu_tests/context_lost_expectations.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e2cfad3bebf1e25258f7a975a45c4c7da3cf3b5d

commit e2cfad3bebf1e25258f7a975a45c4c7da3cf3b5d
Author: Kenneth Russell <kbr@chromium.org>
Date: Tue Oct 16 19:03:51 2018

Revert "Disable ContextLost_WebGLUnblockedAfterUserInitiatedReload"

This reverts commit 9780253fa75f648aea3070fa2079e1f314d33f48.

Reason for revert: test failure was real, and caused by https://chromium-review.googlesource.com/1267235 , which has since been reverted.

Original change's description:
> Disable ContextLost_WebGLUnblockedAfterUserInitiatedReload
> 
> gpu_tests.context_lost_integration_test.ContextLostIntegrationTest.ContextLost_WebGLUnblockedAfterUserInitiatedReload in context_lost_tests
> is flaky on Win10 Debug
> 
> TBR=kbr@chromium.org
> 
> Bug:  895765 ,  879423 
> Change-Id: Ic36400494df68f257329e040be2c72f1ad2ec3a6
> Reviewed-on: https://chromium-review.googlesource.com/c/1283049
> Commit-Queue: Christos Froussios <cfroussios@chromium.org>
> Reviewed-by: Christos Froussios <cfroussios@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#599973}

TBR=kbr@chromium.org,cfroussios@chromium.org

Change-Id: I33951694d070e6eb183eba9a05d9ea517f81ce65
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  895765 ,  879423 
Reviewed-on: https://chromium-review.googlesource.com/c/1283945
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600061}
[modify] https://crrev.com/e2cfad3bebf1e25258f7a975a45c4c7da3cf3b5d/content/test/gpu/gpu_tests/context_lost_expectations.py

There are no failures of this test in the last 200 builds on this waterfall bot:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Android%20FYI%20Release%20%28Nexus%205X%29?limit=200

Closing this out as fixed, at least for the time being.