Destruct base::Thread before WorkerThread::terminateAndWait returns

third_party/WebKit/Source/core/workers/WorkerThread.cpp

Index: third_party/WebKit/Source/core/workers/WorkerThread.cpp
diff --git a/third_party/WebKit/Source/core/workers/WorkerThread.cpp b/third_party/WebKit/Source/core/workers/WorkerThread.cpp
index 8b7022d3a76fc3ebc41a1b27fa30e761d8ca852d..c90a289b0e87641e80cf94abda8b850b7b679c2a 100644
--- a/third_party/WebKit/Source/core/workers/WorkerThread.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerThread.cpp
@@ -215,6 +215,9 @@ void WorkerThread::terminateAndWait()
     // not work.
     terminateInternal(TerminationMode::Forcible);
     m_shutdownEvent->wait();
+
+    // Destruct base::Thread and join the underlying system thread.
+    clearWorkerBackingThread();
 }
 
 void WorkerThread::terminateAndWaitForAllWorkers()