Destruct base::Thread before WorkerThread::terminateAndWait returns

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

Index: third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp
diff --git a/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp b/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp
index 96215255b136d4aac3045c937c1bc033dc919f54..15ff064293306fedca99e7774fbe48f5041d1e77 100644
--- a/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp
+++ b/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp
@@ -53,6 +53,11 @@ ServiceWorkerThread::~ServiceWorkerThread()
 {
 }
 
+void ServiceWorkerThread::clearWorkerBackingThread()
+{
+    m_workerBackingThread = nullptr;
+}
+
 WorkerOrWorkletGlobalScope* ServiceWorkerThread::createWorkerGlobalScope(std::unique_ptr<WorkerThreadStartupData> startupData)
 {
     return ServiceWorkerGlobalScope::create(this, std::move(startupData));