Add live mode detection in WebM MediaSource parser.

media/base/demuxer.h

Index: media/base/demuxer.h
diff --git a/media/base/demuxer.h b/media/base/demuxer.h
index 581bc0075f6f5023da5970308a6b99614a718861..24ea281ac6fffb7c9f8ec5a34e8ead88db94be89 100644
--- a/media/base/demuxer.h
+++ b/media/base/demuxer.h
@@ -44,6 +44,12 @@ class MEDIA_EXPORT DemuxerHost {
 
 class MEDIA_EXPORT Demuxer {
  public:
+  enum Liveness {
+    LIVENESS_UNKNOWN,
+    LIVENESS_RECORDED,
+    LIVENESS_LIVE,
+  };
+
   // A new potentially encrypted stream has been parsed.
   // First parameter - The type of initialization data.
   // Second parameter - The initialization data associated with the stream.
@@ -92,6 +98,9 @@ class MEDIA_EXPORT Demuxer {
   // a null Time is returned.
   virtual base::Time GetTimelineOffset() const = 0;
 
+  // Returns liveness of the stream, i.e. whether it is recorded or live.
+  virtual Liveness GetLiveness() const = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(Demuxer);
 };