Gardening: shared-worker-performance-timeline.html is passing.

It passes locally and flakiness dashboard shows it's been passing for as
far as the results go.

Bug: 711529
TBR: kinuko
Change-Id: Ia9c75b49639c752d9d92ccbf0ee10c4cf0b3c37a
Reviewed-on: https://chromium-review.googlesource.com/995752Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548057}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1531,7 +1531,6 @@ crbug.com/704259 external/wpt/content-security-policy/reporting/reporting-api-se
 crbug.com/711529 http/tests/origin_trials/sample-api-workers.html [ Crash Timeout ]
 crbug.com/711529 http/tests/permissions/test-api-surface.html [ Timeout ]
 crbug.com/711529 http/tests/permissions/test-query.html [ Timeout ]
-crbug.com/711529 http/tests/workers/shared-worker-performance-timeline.html [ Timeout ]
 
 # This test requires enabling the flag CustomUserTiming in a virtual test.
 crbug.com/758385 http/tests/performance-timing/custom-user-timing/po-customusertiming-mark.html [ Skip ]