Terminate and wait the worker thread in ~WebEmbeddedWorkerImpl()

It is possible that termination of worker thread is not triggered by the
time of WebEmbeddedWorkerImpl destruction. We should call
WorkerThread::stop() before waiting for the termination of worker thread.

BUG=426332

Review URL: https://codereview.chromium.org/704063002

git-svn-id: svn://svn.chromium.org/blink/trunk@184900 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -416,6 +416,12 @@ void WorkerThread::stopInShutdownSequence()
     stopInternal();
 }
 
+void WorkerThread::terminateAndWait()
+{
+    stop();
+    m_terminationEvent->wait();
+}
+
 bool WorkerThread::terminated()
 {
     MutexLocker lock(m_threadCreationMutex);

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

@@ -69,6 +69,7 @@ public:
     WebWaitableEvent* shutdownEvent() { return m_shutdownEvent.get(); }
 
     WebWaitableEvent* terminationEvent() { return m_terminationEvent.get(); }
+    void terminateAndWait();
     static void terminateAndWaitForAllWorkers();
 
     bool isCurrentThread() const;

third_party/WebKit/Source/web/WebEmbeddedWorkerImpl.cpp

@@ -51,7 +51,6 @@
 #include "platform/network/ContentSecurityPolicyParsers.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebURLRequest.h"
-#include "public/platform/WebWaitableEvent.h"
 #include "public/web/WebDevToolsAgent.h"
 #include "public/web/WebServiceWorkerContextClient.h"
 #include "public/web/WebServiceWorkerNetworkProvider.h"
@@ -172,10 +171,8 @@ WebEmbeddedWorkerImpl::WebEmbeddedWorkerImpl(
 
 WebEmbeddedWorkerImpl::~WebEmbeddedWorkerImpl()
 {
-    if (m_workerThread) {
-        ASSERT(m_workerThread->terminated());
-        m_workerThread->terminationEvent()->wait();
-    }
+    if (m_workerThread)
+        m_workerThread->terminateAndWait();
 
     ASSERT(runningWorkerInstances().contains(this));
     runningWorkerInstances().remove(this);