Enable Oilpan by default in modules/filesystem/

Source/modules/filesystem/DOMFileSystemBase.cpp

Index: Source/modules/filesystem/DOMFileSystemBase.cpp
diff --git a/Source/modules/filesystem/DOMFileSystemBase.cpp b/Source/modules/filesystem/DOMFileSystemBase.cpp
index 893b46f23952f4e3ab23effd7f6bb4fda9491194..7d490d34249667df3a26e991331374aa3c0752e7 100644
--- a/Source/modules/filesystem/DOMFileSystemBase.cpp
+++ b/Source/modules/filesystem/DOMFileSystemBase.cpp
@@ -320,7 +320,7 @@ void DOMFileSystemBase::getDirectory(const EntryBase* entry, const String& path,
         fileSystem()->directoryExists(createFileSystemURL(absolutePath), callbacks.release());
 }
 
-int DOMFileSystemBase::readDirectory(PassRefPtrWillBeRawPtr<DirectoryReaderBase> reader, const String& path, PassOwnPtr<EntriesCallback> successCallback, PassOwnPtr<ErrorCallback> errorCallback, SynchronousType synchronousType)
+int DOMFileSystemBase::readDirectory(DirectoryReaderBase* reader, const String& path, PassOwnPtr<EntriesCallback> successCallback, PassOwnPtr<ErrorCallback> errorCallback, SynchronousType synchronousType)
 {
     ASSERT(DOMFilePath::isAbsolute(path));