DecoderControl: use std::chrono::duration for start_ms and end_ms

src/decoder/DecoderControl.hxx

@@ -127,21 +127,20 @@ struct DecoderControl {
 	DetachedSong *song;
 
 	/**
-	 * The initial seek position (in milliseconds), e.g. to the
-	 * start of a sub-track described by a CUE file.
+	 * The initial seek position, e.g. to the start of a sub-track
+	 * described by a CUE file.
 	 *
 	 * This attribute is set by Start().
 	 */
-	unsigned start_ms;
+	SongTime start_time;
 
 	/**
-	 * The decoder will stop when it reaches this position (in
-	 * milliseconds).  0 means don't stop before the end of the
-	 * file.
+	 * The decoder will stop when it reaches this position.  0
+	 * means don't stop before the end of the file.
 	 *
 	 * This attribute is set by Start().
 	 */
-	unsigned end_ms;
+	SongTime end_time;
 
 	float total_time;
 
@@ -356,12 +355,12 @@ public:
 	 *
 	 * @param song the song to be decoded; the given instance will be
 	 * owned and freed by the decoder
-	 * @param start_ms see #DecoderControl
-	 * @param end_ms see #DecoderControl
+	 * @param start_time see #DecoderControl
+	 * @param end_time see #DecoderControl
 	 * @param pipe the pipe which receives the decoded chunks (owned by
 	 * the caller)
 	 */
-	void Start(DetachedSong *song, unsigned start_ms, unsigned end_ms,
+	void Start(DetachedSong *song, SongTime start_time, SongTime end_time,
 		   MusicBuffer &buffer, MusicPipe &pipe);
 
 	void Stop();