Implemented availability control for gstreamer player backend

Change-Id: I6d736b90ad59e258eb6f20befea8cfe1afce423a
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>
Reviewed-by: Jonas Rabbe <jonas.rabbe@nokia.com>

src/plugins/gstreamer/mediaplayer/qgstreamerplayercontrol.cpp

@@ -127,6 +127,11 @@ QGstreamerPlayerControl::~QGstreamerPlayerControl()
     }
 }
 
+QMediaPlayerResourceSetInterface* QGstreamerPlayerControl::resources() const
+{
+    return m_resources;
+}
+
 qint64 QGstreamerPlayerControl::position() const
 {
     return m_seekToStartPending ? 0 : m_session->position();