Fix seeking when the start time is non-zero.

media/filters/chunk_demuxer.cc

Index: media/filters/chunk_demuxer.cc
diff --git a/media/filters/chunk_demuxer.cc b/media/filters/chunk_demuxer.cc
index 3341fcc86bc53bd80d9500c1dca93a32cc807a42..34356d0a368c3f9dfbd5999b68bd09f00d5ddbce 100644
--- a/media/filters/chunk_demuxer.cc
+++ b/media/filters/chunk_demuxer.cc
@@ -1091,10 +1091,6 @@ DemuxerStream* ChunkDemuxer::GetStream(DemuxerStream::Type type) {
   return NULL;
 }
 
-TimeDelta ChunkDemuxer::GetStartTime() const {
-  return TimeDelta();
-}
-
 base::Time ChunkDemuxer::GetTimelineOffset() const {
   return timeline_offset_;
 }
@@ -1596,7 +1592,7 @@ void ChunkDemuxer::OnSourceInitDone(
     return;
   }
 
-  SeekAllSources(GetStartTime());
+  SeekAllSources(base::TimeDelta());
   StartReturningData();
 
   if (duration_ == kNoTimestamp())