[Linux] Use DBus for following media playback change

linux/media/playerstatuswatcher.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <QObject>
+#include <QDBusInterface>
+#include <QDBusServiceWatcher>
+
+class PlayerStatusWatcher : public QObject {
+    Q_OBJECT
+public:
+    explicit PlayerStatusWatcher(const QString &playerService, QObject *parent = nullptr);
+
+signals:
+    void playbackStatusChanged(const QString &status);
+
+private slots:
+    void onPropertiesChanged(const QString &interface, const QVariantMap &changed, const QStringList &);
+    void onServiceOwnerChanged(const QString &name, const QString &oldOwner, const QString &newOwner);
+
+private:
+    void updateStatus();
+    QString m_playerService;
+    QDBusInterface *m_iface;
+    QDBusServiceWatcher *m_serviceWatcher;
+};