Fix flaky shared worker blink web tests

The condition before invoking |terminate_all_workers_callback_| in
TestSharedWorkerServiceImpl::OnRemoteSharedWorkerConnectionLost() should
match the one in DestroyHost(). Both of these functions can be invoked
when the callback is not set.

Bug: 1008257
Change-Id: I9dd5f7812bbe01dfba8bb3a5fca0481e6a4ee7aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1862892
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706270}

content/browser/worker_host/test_shared_worker_service_impl.cc

@@ -82,8 +82,10 @@ void TestSharedWorkerServiceImpl::OnRemoteSharedWorkerConnectionLost(
     mojo::RemoteSetElementId id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  if (worker_hosts_.empty() && workers_awaiting_disconnection_.empty())
+  if (worker_hosts_.empty() && workers_awaiting_disconnection_.empty() &&
+      terminate_all_workers_callback_) {
     std::move(terminate_all_workers_callback_).Run();
+  }
 }
 
 }  // namespace content

third_party/blink/web_tests/TestExpectations

@@ -5660,10 +5660,6 @@ crbug.com/630695 virtual/scalefactor200/css3/filters/effect-drop-shadow-hw.html
 # Sheriff 2019-09-20
 crbug.com/1005128 crypto/subtle/abandon-crypto-operation2.html [ Pass Crash ]
 
-# Sheriff 2019-09-26
-crbug.com/1008257 external/wpt/service-workers/service-worker/claim-shared-worker-fetch.https.html [ Pass Crash ]
-crbug.com/1008257 external/wpt/service-workers/service-worker/worker-interception-redirect.https.html [ Pass Crash ]
-
 # Sheriff 2019-09-27
 crbug.com/1008826 [ Mac10.13 ] http/tests/security/frameNavigation/xss-ALLOWED-parent-navigation-change.html [ Pass Failure Timeout ]