Decryptors can report kNoKey to WebMediaPlayer

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 67da6c0c7be6d0d6b9fa051d7ec4ed70c053ad59..19256ceef194f573d9f3a30bf7d7c3f6eca7b6a3 100644
--- a/media/filters/decrypting_audio_decoder.h
+++ b/media/filters/decrypting_audio_decoder.h
@@ -39,7 +39,8 @@ class MEDIA_EXPORT DecryptingAudioDecoder : 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;
@@ -96,6 +97,7 @@ class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
   OutputCB output_cb_;
   DecodeCB decode_cb_;
   base::Closure reset_cb_;
+  base::Closure waiting_for_encryption_key_cb_;
 
   // The current decoder configuration.
   AudioDecoderConfig config_;