Add live mode detection in WebM MediaSource parser.

media/filters/ffmpeg_demuxer.cc

Index: media/filters/ffmpeg_demuxer.cc
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index d54db072725801e754db463d2a00b5f299d2cf94..40a8c917c9000e5d3c777a2977d5e762f8af165b 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -394,6 +394,7 @@ FFmpegDemuxer::FFmpegDemuxer(
       media_log_(media_log),
       bitrate_(0),
       start_time_(kNoTimestamp()),
+      liveness_(LIVENESS_UNKNOWN),
       audio_disabled_(false),
       text_enabled_(false),
       duration_known_(false),
@@ -506,6 +507,11 @@ base::Time FFmpegDemuxer::GetTimelineOffset() const {
   return timeline_offset_;
 }
 
+Demuxer::Liveness FFmpegDemuxer::GetLiveness() const {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  return liveness_;
+}
+
 void FFmpegDemuxer::AddTextStreams() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
@@ -696,6 +702,14 @@ void FFmpegDemuxer::OnFindStreamInfoDone(const PipelineStatusCB& status_cb,
 
   timeline_offset_ = ExtractTimelineOffset(format_context);
 
+  if (max_duration == kInfiniteDuration() && !timeline_offset_.is_null()) {
+    liveness_ = LIVENESS_LIVE;
+  } else if (max_duration != kInfiniteDuration()) {
+    liveness_ = LIVENESS_RECORDED;
+  } else {
+    liveness_ = LIVENESS_UNKNOWN;
+  }
+
   // Good to go: set the duration and bitrate and notify we're done
   // initializing.
   host_->SetDuration(max_duration);