Remove DecryptingAudioDecoder::kSupportedBitsPerChannel which is not used

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 5fdb6f848683e5fee66ea391f29479160e960220..ddb89acfbd7d769c44f0849842869fc7d60cf998 100644
--- a/media/filters/decrypting_audio_decoder.h
+++ b/media/filters/decrypting_audio_decoder.h
@@ -30,13 +30,6 @@ class Decryptor;
 // that no locks are required for thread safety.
 class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
  public:
-  // We do not currently have a way to let the Decryptor choose the output
-  // audio sample format and notify us of its choice. Therefore, we require all
-  // Decryptor implementations to decode audio into a fixed integer sample
-  // format designated by kSupportedBitsPerChannel.
-  // TODO(xhwang): Remove this restriction after http://crbug.com/169105 fixed.
-  static const int kSupportedBitsPerChannel;
-
   DecryptingAudioDecoder(
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
       const SetDecryptorReadyCB& set_decryptor_ready_cb);