Decryptors can report kNoKey to WebMediaPlayer

media/filters/ffmpeg_audio_decoder.h

Index: media/filters/ffmpeg_audio_decoder.h
diff --git a/media/filters/ffmpeg_audio_decoder.h b/media/filters/ffmpeg_audio_decoder.h
index c9429f989de9b0dbbce612d96be77186b846d4e9..6d4ed11608bb746fb38047c4b46d681c2256a434 100644
--- a/media/filters/ffmpeg_audio_decoder.h
+++ b/media/filters/ffmpeg_audio_decoder.h
@@ -39,7 +39,8 @@ class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
   std::string GetDisplayName() const override;
   void Initialize(const AudioDecoderConfig& config,
                   const PipelineStatusCB& status_cb,
-                  const OutputCB& output_cb) override;
+                  const OutputCB& output_cb,
+                  const base::Closure& waiting_for_encryption_key_cb) override;
   void Decode(const scoped_refptr<DecoderBuffer>& buffer,
               const DecodeCB& decode_cb) override;
   void Reset(const base::Closure& closure) override;