Introduce WorkerBackingThread

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 ffd253c304a0c8766f4a21ea3f2cfb45574cb9a3..a86b328a148a6e5df81fc23530f6c17b1d006b93 100644
--- a/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp
+++ b/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerThread.cpp
@@ -30,6 +30,7 @@
 
 #include "modules/serviceworkers/ServiceWorkerThread.h"
 
+#include "core/workers/WorkerBackingThread.h"
 #include "core/workers/WorkerThreadStartupData.h"
 #include "modules/serviceworkers/ServiceWorkerGlobalScope.h"
 
@@ -42,6 +43,7 @@ PassOwnPtr<ServiceWorkerThread> ServiceWorkerThread::create(PassRefPtr<WorkerLoa
 
 ServiceWorkerThread::ServiceWorkerThread(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, WorkerReportingProxy& workerReportingProxy)
     : WorkerThread(workerLoaderProxy, workerReportingProxy)
+    , m_workerBackingThread(WorkerBackingThread::create("ServiceWorker Thread"))
 {
 }
 
@@ -54,11 +56,4 @@ RawPtr<WorkerGlobalScope> ServiceWorkerThread::createWorkerGlobalScope(PassOwnPt
     return ServiceWorkerGlobalScope::create(this, startupData);
 }
 
-WebThreadSupportingGC& ServiceWorkerThread::backingThread()
-{
-    if (!m_thread)
-        m_thread = WebThreadSupportingGC::create("ServiceWorker Thread");
-    return *m_thread.get();
-}
-
 } // namespace blink