Oilpan: make DOMWindowProperty a GC mixin.

Source/modules/serviceworkers/NavigatorServiceWorker.cpp

Index: Source/modules/serviceworkers/NavigatorServiceWorker.cpp
diff --git a/Source/modules/serviceworkers/NavigatorServiceWorker.cpp b/Source/modules/serviceworkers/NavigatorServiceWorker.cpp
index f929fe53236d83606eef4c4338be67143bf364cd..e7427042c04d70739ad026c52b8a36b670ff4f7d 100644
--- a/Source/modules/serviceworkers/NavigatorServiceWorker.cpp
+++ b/Source/modules/serviceworkers/NavigatorServiceWorker.cpp
@@ -18,9 +18,7 @@ NavigatorServiceWorker::NavigatorServiceWorker(Navigator& navigator)
 {
 }
 
-NavigatorServiceWorker::~NavigatorServiceWorker()
-{
-}
+DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(NavigatorServiceWorker);
 
 NavigatorServiceWorker* NavigatorServiceWorker::from(Document& document)
 {
@@ -78,6 +76,7 @@ void NavigatorServiceWorker::trace(Visitor* visitor)
 {
     visitor->trace(m_serviceWorker);
     WillBeHeapSupplement<Navigator>::trace(visitor);
+    DOMWindowProperty::trace(visitor);
 }
 
 } // namespace blink