[Background Sync] Converting Blink code to the MVP API

Source/modules/background_sync/ServiceWorkerRegistrationSync.cpp

Index: Source/modules/background_sync/ServiceWorkerRegistrationSync.cpp
diff --git a/Source/modules/background_sync/ServiceWorkerRegistrationSync.cpp b/Source/modules/background_sync/ServiceWorkerRegistrationSync.cpp
index e169b8a640d7983508f69b627753f7cce9bdcf27..67516eee0e58732b086e04b55127a06cf6797965 100644
--- a/Source/modules/background_sync/ServiceWorkerRegistrationSync.cpp
+++ b/Source/modules/background_sync/ServiceWorkerRegistrationSync.cpp
@@ -5,6 +5,7 @@
 #include "config.h"
 #include "modules/background_sync/ServiceWorkerRegistrationSync.h"
 
+#include "modules/background_sync/PeriodicSyncManager.h"
 #include "modules/background_sync/SyncManager.h"
 #include "modules/serviceworkers/ServiceWorkerRegistration.h"
 
@@ -34,22 +35,35 @@ ServiceWorkerRegistrationSync& ServiceWorkerRegistrationSync::from(ServiceWorker
     return *supplement;
 }
 
-SyncManager* ServiceWorkerRegistrationSync::syncManager(ServiceWorkerRegistration& registration)
+SyncManager* ServiceWorkerRegistrationSync::sync(ServiceWorkerRegistration& registration)
 {
-    return ServiceWorkerRegistrationSync::from(registration).syncManager();
+    return ServiceWorkerRegistrationSync::from(registration).sync();
 }
 
-SyncManager* ServiceWorkerRegistrationSync::syncManager()
+SyncManager* ServiceWorkerRegistrationSync::sync()
 {
     if (!m_syncManager)
         m_syncManager = SyncManager::create(m_registration);
     return m_syncManager.get();
 }
 
+PeriodicSyncManager* ServiceWorkerRegistrationSync::periodicSync(ServiceWorkerRegistration& registration)
+{
+    return ServiceWorkerRegistrationSync::from(registration).periodicSync();
+}
+
+PeriodicSyncManager* ServiceWorkerRegistrationSync::periodicSync()
+{
+    if (!m_periodicSyncManager)
+        m_periodicSyncManager = PeriodicSyncManager::create(m_registration);
+    return m_periodicSyncManager.get();
+}
+
 DEFINE_TRACE(ServiceWorkerRegistrationSync)
 {
     visitor->trace(m_registration);
     visitor->trace(m_syncManager);
+    visitor->trace(m_periodicSyncManager);
     HeapSupplement<ServiceWorkerRegistration>::trace(visitor);
 }