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 e84a426f25e05d690601c253b87bad7ea8266475..efa391c3618954eb75fcea4d4dc08583e6c68915 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 @@ WorkerGlobalScope* ServiceWorkerThread::createWorkerGlobalScope(PassOwnPtr<Worke
     return ServiceWorkerGlobalScope::create(this, startupData);
 }
 
-WebThreadSupportingGC& ServiceWorkerThread::backingThread()
-{
-    if (!m_thread)
-        m_thread = WebThreadSupportingGC::create("ServiceWorker Thread");
-    return *m_thread.get();
-}
-
 } // namespace blink