Added method to get metadata out of the player.

The method passes a list of metadata ids to be retrieved and
a parcel where the metadata records should be appended.

If the list of ids is empty, all the metadata should be returned.
diff --git a/media/libmediaplayerservice/MidiFile.h b/media/libmediaplayerservice/MidiFile.h
index 83d97fe..30b6a2e 100644
--- a/media/libmediaplayerservice/MidiFile.h
+++ b/media/libmediaplayerservice/MidiFile.h
@@ -46,7 +46,13 @@
     virtual status_t    reset();
     virtual status_t    setLooping(int loop);
     virtual player_type playerType() { return SONIVOX_PLAYER; }
-    virtual status_t    invoke(const Parcel& request, Parcel *reply) {return INVALID_OPERATION;}
+    virtual status_t    invoke(const Parcel& request, Parcel *reply) {
+        return INVALID_OPERATION;
+    }
+    virtual status_t    getMetadata(const SortedVector<MetadataType>& ids,
+                                    Parcel *records)  {
+        return INVALID_OPERATION;
+    }
 
 private:
             status_t    createOutputTrack();