Log is here: https://logs.chromium.org/v/?s=chrome%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8933673880000529392%2F%2B%2Fblink_perf.css_32f5538c-3ae6-408b-adc8-2967576ad79b

We're getting a timeout trying to talk to Chrome Web View:

Traceback (most recent call last):
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/story_runner.py", line 126, in _RunStoryAndProcessErrorIfNeeded
    state.RunStory(results)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/page/shared_page_state.py", line 300, in RunStory
    self._current_page.Run(self)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/page/__init__.py", line 95, in Run
    shared_state.page_test.RunNavigateSteps(self, current_tab)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/page/legacy_page_test.py", line 152, in RunNavigateSteps
    page.RunNavigateSteps(action_runner)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/page/__init__.py", line 104, in RunNavigateSteps
    url, script_to_evaluate_on_commit=self.script_to_evaluate_on_commit)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/actions/action_runner.py", line 186, in Navigate
    timeout_in_seconds=timeout_in_seconds))
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/actions/action_runner.py", line 62, in _RunAction
    action.RunAction(self._tab)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/actions/navigate.py", line 27, in RunAction
    tab.WaitForDocumentReadyStateToBeInteractiveOrBetter(time_left_in_seconds)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/browser/web_contents.py", line 103, in WaitForDocumentReadyStateToBeInteractiveOrBetter
    'document.readyState == "complete"', timeout=timeout)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/browser/web_contents.py", line 239, in WaitForJavaScriptCondition
    return self._inspector_backend.WaitForJavaScriptCondition(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 290, in WaitForJavaScriptCondition
    return py_utils.WaitFor(IsJavaScriptExpressionTrue, timeout)
  File "/b/swarming/w/ir/third_party/catapult/common/py_utils/py_utils/__init__.py", line 129, in WaitFor
    res = condition()
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 287, in IsJavaScriptExpressionTrue
    return self._EvaluateJavaScript(condition, context_id, timeout)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 41, in Inner
    inspector_backend._ConvertExceptionFromInspectorWebsocket(e)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 38, in Inner
    return func(inspector_backend, *args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 540, in _EvaluateJavaScript
    self._runtime.Crash(context_id, timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_runtime.py", line 81, in Crash
    res = self._inspector_websocket.SyncRequest(request, timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 129, in SyncRequest
    self._SendRequest(req)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 119, in _SendRequest
    raise WebSocketException(err)
TimeoutException

Looks like the root cause is:

"android:id/message['Unfortunately, WebView Shell has stopped.']"

Planning to disable the failing test following https://chromium.googlesource.com/chromium/src/+/master/docs/speed/bot_health_sheriffing/how_to_disable_a_story.md

I am waiting on issue 891863 to figure out how to launch a bisection of this.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a320b47bcb30fc014474e3ae01ed6b23e6e4746f

commit a320b47bcb30fc014474e3ae01ed6b23e6e4746f
Author: Caleb Rouleau <crouleau@chromium.org>
Date: Wed Oct 03 21:29:12 2018

[blink_perf.css] Disable failing test CustomPropertiesVarAlias.html

NOTRY=true
TBR=nednguyen@google.com
CC=andruud@chromium.org,futhark@chromium.org

Bug: 891878
Change-Id: I52e2b98faee15e90b2d6dbb71f1d572fa64c5ab7
Reviewed-on: https://chromium-review.googlesource.com/c/1259617
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596373}
[modify] https://crrev.com/a320b47bcb30fc014474e3ae01ed6b23e6e4746f/tools/perf/expectations.config

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