FileSystem: Modify ObfucatedFileUtil to delete contents of the plugin private filesystem

storage/browser/fileapi/plugin_private_file_system_backend.cc

Index: storage/browser/fileapi/plugin_private_file_system_backend.cc
diff --git a/storage/browser/fileapi/plugin_private_file_system_backend.cc b/storage/browser/fileapi/plugin_private_file_system_backend.cc
index 6874de4d650597310716b206ad2176c2cf5a2081..e4593c9f0850532109fb2cf90fd8ee4cb483e902 100644
--- a/storage/browser/fileapi/plugin_private_file_system_backend.cc
+++ b/storage/browser/fileapi/plugin_private_file_system_backend.cc
@@ -223,8 +223,8 @@ PluginPrivateFileSystemBackend::DeleteOriginDataOnFileTaskRunner(
     FileSystemType type) {
   if (!CanHandleType(type))
     return base::File::FILE_ERROR_SECURITY;
-  bool result = obfuscated_file_util()->DeleteDirectoryForOriginAndType(
-      origin_url, std::string());
+  bool result = obfuscated_file_util()->
+      DeleteOriginDirectoryForPluginPrivateFileSystem(origin_url);
   if (result)
     return base::File::FILE_OK;
   return base::File::FILE_ERROR_FAILED;