Enable Oilpan by default in modules/filesystem/

Source/modules/filesystem/SyncCallbackHelper.h

Index: Source/modules/filesystem/SyncCallbackHelper.h
diff --git a/Source/modules/filesystem/SyncCallbackHelper.h b/Source/modules/filesystem/SyncCallbackHelper.h
index 4edb746050151409db1ab72d6f774be01034b5ea..0e24d5921641b45156f55f2df58f12bbb812b83d 100644
--- a/Source/modules/filesystem/SyncCallbackHelper.h
+++ b/Source/modules/filesystem/SyncCallbackHelper.h
@@ -53,8 +53,8 @@ template <typename ResultType, typename CallbackArg>
 struct HelperResultType {
     DISALLOW_ALLOCATION();
 public:
-    typedef PassRefPtrWillBeRawPtr<ResultType> ReturnType;
-    typedef RefPtrWillBePersistent<ResultType> StorageType;
+    typedef ResultType* ReturnType;
+    typedef Persistent<ResultType> StorageType;
 
     static ReturnType createFromCallbackArg(CallbackArg argument)
     {
@@ -157,8 +157,8 @@ private:
     bool m_completed;
 };
 
-struct EmptyType : public RefCountedWillBeGarbageCollected<EmptyType> {
-    static PassRefPtrWillBeRawPtr<EmptyType> create(EmptyType*)
+struct EmptyType : public GarbageCollected<EmptyType> {
+    static EmptyType* create(EmptyType*)
     {
         return nullptr;
     }