FFmpegDemuxer should fall back to disabled streams for seeking

media/filters/ffmpeg_demuxer.h

Index: media/filters/ffmpeg_demuxer.h
diff --git a/media/filters/ffmpeg_demuxer.h b/media/filters/ffmpeg_demuxer.h
index 6c065de24f66136852e05dc2788173b24d1cf8b1..670499dd0ba13f96339ccb0eb66ab5ba30dfab51 100644
--- a/media/filters/ffmpeg_demuxer.h
+++ b/media/filters/ffmpeg_demuxer.h
@@ -328,10 +328,15 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
   // based timeline.
   base::TimeDelta start_time_;
 
+  // Finds the stream with the lowest known start time (i.e. not kNoTimestamp
+  // start time) with enabled status matching |enabled|.
+  FFmpegDemuxerStream* FindStreamWithLowestStartPts(bool enabled);

[DaleCurtis, 2016/12/06 20:18:03]

StartTimestamp

s/enabled/ignore_disabled_streams/ ?

[servolk, 2016/12/06 22:12:25]

Done: FindStreamWithLowestStartPts -> FindStreamWithLowestStartTimestamp

Re. ignore_disabled_streams - that would be actually misleading, since currently
FindStreamWithLowestStartTimestamp considers only streams that are enabled or
disabled, i.e. streams with enabled() matching the enabled parameter, so
currently calling FindStreamWithLowestStartTimestamp(false) would return the
stream with lowest start time among disabled streams only. If the input
parameter was names ignore_disabled_streams then I'd expected
FindStreamWithLowestStartTimestamp(false) to return the stream with lowest start
time among enabled and disabled streams.

+
   // Finds a preferred stream for seeking to |seek_time|. Preference is
   // typically given to video streams, unless the |seek_time| is earlier than
   // the start time of the video stream. In that case a stream with the earliest
-  // start time is preferred. Disabled streams are not considered.
+  // start time is preferred. Disabled streams are considered only as the last
+  // fallback option.
   FFmpegDemuxerStream* FindPreferredStreamForSeeking(base::TimeDelta seek_time);
 
   // The Time associated with timestamp 0. Set to a null