Remove locking from FFmpegDemuxerStream and associated TODOs from media code.

media/filters/decrypting_audio_decoder.h

Index: media/filters/decrypting_audio_decoder.h
diff --git a/media/filters/decrypting_audio_decoder.h b/media/filters/decrypting_audio_decoder.h
index 4fb08c8a50938869e33f7ecfa39eb87404cc24e5..8f732d5812e2c5a0d11db9a8169244bf7a0299eb 100644
--- a/media/filters/decrypting_audio_decoder.h
+++ b/media/filters/decrypting_audio_decoder.h
@@ -96,11 +96,6 @@ class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
   void ReadFromDemuxerStream();
 
   // Callback for DemuxerStream::Read().
-  void DecryptAndDecodeBuffer(DemuxerStream::Status status,
-                              const scoped_refptr<DecoderBuffer>& buffer);
-
-  // Carries out the buffer decrypting/decoding operation scheduled by
-  // DecryptAndDecodeBuffer().
   void DoDecryptAndDecodeBuffer(DemuxerStream::Status status,
                                 const scoped_refptr<DecoderBuffer>& buffer);