Support earliest seekable time in WMPI.

media/base/pipeline.h

Index: media/base/pipeline.h
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index a666fc1307dc673931be1be55c34e62e5670e594..5fca64a6814da474df6590640c0f23b60667fd82 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -170,6 +170,9 @@ class MEDIA_EXPORT Pipeline : public DemuxerHost {
   // Get approximate time ranges of buffered media.
   Ranges<base::TimeDelta> GetBufferedTimeRanges() const;
 
+  // Get the start time of the media, or zero if not known.
+  base::TimeDelta GetMediaStartTime() const;
+
   // Get the duration of the media in microseconds.  If the duration has not
   // been determined yet, then returns 0.
   base::TimeDelta GetMediaDuration() const;