Worker: Wait for termination by WorkerThreadLifecycleObserver instead of WaitableEvent

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 9588cd07371729bf75118303720b776d55716a71..28da9d0141874da39b2dadd796626f294d6837a3 100644
--- a/third_party/WebKit/Source/core/workers/WorkerThread.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerThread.cpp
@@ -336,9 +336,6 @@ WorkerThread::WorkerThread(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, Work
     , m_inspectorTaskRunner(wrapUnique(new InspectorTaskRunner()))
     , m_workerLoaderProxy(workerLoaderProxy)
     , m_workerReportingProxy(workerReportingProxy)
-    , m_terminationEvent(wrapUnique(new WaitableEvent(
-        WaitableEvent::ResetPolicy::Manual,
-        WaitableEvent::InitialState::NonSignaled)))
     , m_shutdownEvent(wrapUnique(new WaitableEvent(
         WaitableEvent::ResetPolicy::Manual,
         WaitableEvent::InitialState::NonSignaled)))
@@ -390,10 +387,6 @@ void WorkerThread::terminateInternal(TerminationMode mode)
         }
         m_terminated = true;
 
-        // Signal the thread to notify that the thread's stopping.
-        if (m_terminationEvent)
-            m_terminationEvent->signal();
-
         if (!hasBeenInitialized) {
             // If the worker thread was never initialized, don't start another
             // shutdown, but still wait for the thread to signal when shutdown