Encrypted Media: DecryptingXxx::SetDecryptor() accepts NULL decryptor.

media/filters/decrypting_audio_decoder.cc

Index: media/filters/decrypting_audio_decoder.cc
diff --git a/media/filters/decrypting_audio_decoder.cc b/media/filters/decrypting_audio_decoder.cc
index f908d9b504cb4ddaa09743c7c02b767973ec90cc..8aee1411ef7336aef8e871da8fe917d2ee16680c 100644
--- a/media/filters/decrypting_audio_decoder.cc
+++ b/media/filters/decrypting_audio_decoder.cc
@@ -173,6 +173,14 @@ void DecryptingAudioDecoder::SetDecryptor(Decryptor* decryptor) {
   DCHECK(!set_decryptor_ready_cb_.is_null());
 
   set_decryptor_ready_cb_.Reset();
+
+  if (!decryptor) {
+    base::ResetAndReturn(&init_cb_).Run(DECODER_ERROR_NOT_SUPPORTED);
+    // TODO(xhwang): Add kError state. See http://crbug.com/251503
+    state_ = kDecodeFinished;
+    return;
+  }
+
   decryptor_ = decryptor;
 
   const AudioDecoderConfig& input_config =