Fix mtp device support

src/device/mtpconnection.h

@@ -2,6 +2,7 @@
  * Strawberry Music Player
  * This file was part of Clementine.
  * Copyright 2010, David Sansome <me@davidsansome.com>
+ * Copyright 2019, Jonas Kvinge <jonas@jkvinge.net>
  *
  * Strawberry is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -24,18 +25,23 @@
 #include "config.h"
 
 #include <stdbool.h>
+#include <memory>
 #include <libmtp.h>
 
 #include <QtGlobal>
+#include <QList>
 #include <QUrl>
 
-class MtpConnection {
+#include "core/song.h"
+
+class MtpConnection : public QObject, public std::enable_shared_from_this<MtpConnection> {
 public:
   MtpConnection(const QUrl &url);
   ~MtpConnection();
 
   bool is_valid() const { return device_; }
   LIBMTP_mtpdevice_t *device() const { return device_; }
+  bool GetSupportedFiletypes(QList<Song::FileType> *ret);
 
 private:
   Q_DISABLE_COPY(MtpConnection);
@@ -43,4 +49,4 @@ private:
   LIBMTP_mtpdevice_t *device_;
 };
 
-#endif // MTPCONNECTION_H
+#endif  // MTPCONNECTION_H