Add snap warning dialog

src/dialogs/snapdialog.h

@@ -0,0 +1,41 @@
+/*
+ * Strawberry Music Player
+ * Copyright 2020, 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef SNAPDIALOG_H
+#define SNAPDIALOG_H
+
+#include <QDialog>
+
+class Ui_SnapDialog;
+
+class SnapDialog : public QDialog {
+  Q_OBJECT
+
+ public:
+  explicit SnapDialog(QWidget *parent = nullptr);
+  ~SnapDialog() override;
+
+ private slots:
+  void DoNotShowMessageAgain();
+
+ private:
+  Ui_SnapDialog *ui_;
+};
+
+#endif  // SNAPDIALOG_H