Destruct base::Thread before WorkerThread::terminateAndWait returns

third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 35 matching lines @@
 ServiceWorkerThread::ServiceWorkerThread(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, WorkerReportingProxy& workerReportingProxy)
     : WorkerThread(workerLoaderProxy, workerReportingProxy)
     , m_workerBackingThread(WorkerBackingThread::create("ServiceWorker Thread"))
 {
 }
 
 ServiceWorkerThread::~ServiceWorkerThread()
 {
 }
 
+void ServiceWorkerThread::clearWorkerBackingThread()
+{
+    m_workerBackingThread = nullptr;
+}
+
 WorkerOrWorkletGlobalScope* ServiceWorkerThread::createWorkerGlobalScope(std::unique_ptr<WorkerThreadStartupData> startupData)
 {
     return ServiceWorkerGlobalScope::create(this, std::move(startupData));
 }
 
 } // namespace blink