--- a/content/media/mediasource/MediaSourceReader.cpp
+++ b/content/media/mediasource/MediaSourceReader.cpp
@@ -204,17 +204,16 @@ MediaSourceReader::Shutdown()
   MediaDecoderReader::Shutdown();
   for (uint32_t i = 0; i < mTrackBuffers.Length(); ++i) {
     mTrackBuffers[i]->Shutdown();
   }
   mAudioTrack = nullptr;
   mAudioReader = nullptr;
   mVideoTrack = nullptr;
   mVideoReader = nullptr;
-  mTrackBuffers.Clear();
 }
 
 void
 MediaSourceReader::BreakCycles()
 {
   MediaDecoderReader::BreakCycles();
 
   // These were cleared in Shutdown().