Encrypted Media: No need to cancel NewKeyCB during tear down.

media/filters/decrypting_demuxer_stream.cc

Index: media/filters/decrypting_demuxer_stream.cc
diff --git a/media/filters/decrypting_demuxer_stream.cc b/media/filters/decrypting_demuxer_stream.cc
index 1598be6870a850ff8fbae006ee8f17cbdd2e456e..fe42ef5ba6cd6155e84cd3a714cad7b2b1108424 100644
--- a/media/filters/decrypting_demuxer_stream.cc
+++ b/media/filters/decrypting_demuxer_stream.cc
@@ -124,12 +124,6 @@ void DecryptingDemuxerStream::Stop(const base::Closure& closure) {
   // Destroy()), so running |closure| can't wait for anything that requires the
   // render thread to process messages to complete (such as PPAPI methods).
   if (decryptor_) {
-    // Clear the callback.
-    // TODO(xhwang): Since we invalidate all weak pointers during Stop(),
-    // canceling NewKeyCB seems unnecessary. Clean this up in all Decrypting*
-    // classes.
-    decryptor_->RegisterNewKeyCB(GetDecryptorStreamType(),
-                                 Decryptor::NewKeyCB());
     decryptor_->CancelDecrypt(GetDecryptorStreamType());
     decryptor_ = NULL;
   }