Bug 1289438: [ogg] P5. Don't seek back to first buffered position during reset. r=gerald

A call to reset is always followed by a call to Seek; seeking is an heavy operation with ogg so let's minimize the number of times we are actually seeking.

MozReview-Commit-ID: Jz7dL9IFM14

--HG--
extra : rebase_source : b4c861b5963647292e3c8d8c8b8ac7ce097112fa

dom/media/ogg/OggDemuxer.cpp

@@ -1458,11 +1458,6 @@ OggTrackDemuxer::Reset()
 {
   mParent->Reset(mType);
   mQueuedSample = nullptr;
-  TimeIntervals buffered = GetBuffered();
-  if (buffered.Length()) {
-    OGG_DEBUG("Seek to start point: %f", buffered.Start(0).ToSeconds());
-    mParent->SeekInternal(mType, buffered.Start(0));
-  }
 }
 
 RefPtr<OggTrackDemuxer::SkipAccessPointPromise>