Stop DecryptingDemuxerStream in AudioRendererImpl::Stop().

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 988d5308edccff7b58e17cfe28cbf162578987c8..1598be6870a850ff8fbae006ee8f17cbdd2e456e 100644
--- a/media/filters/decrypting_demuxer_stream.cc
+++ b/media/filters/decrypting_demuxer_stream.cc
@@ -116,7 +116,8 @@ void DecryptingDemuxerStream::Stop(const base::Closure& closure) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(state_ != kUninitialized) << state_;
 
-  // Invalidate all weak pointers so that pending callbacks won't fire.
+  // Invalidate all weak pointers so that pending callbacks won't be fired into
+  // this object.
   weak_factory_.InvalidateWeakPtrs();
 
   // At this point the render thread is likely paused (in WebMediaPlayerImpl's
@@ -124,6 +125,9 @@ void DecryptingDemuxerStream::Stop(const base::Closure& closure) {
   // 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());