Fold {Audio|Video}Decoder::Stop() into the dtor.

media/filters/opus_audio_decoder.cc

Index: media/filters/opus_audio_decoder.cc
diff --git a/media/filters/opus_audio_decoder.cc b/media/filters/opus_audio_decoder.cc
index bf59adf691e671c27535f6dd8c70407e016dec88..cd4992a2bd246a79b6c9e9b113bcde98eb01a338 100644
--- a/media/filters/opus_audio_decoder.cc
+++ b/media/filters/opus_audio_decoder.cc
@@ -281,7 +281,7 @@ void OpusAudioDecoder::Reset(const base::Closure& closure) {
   task_runner_->PostTask(FROM_HERE, closure);
 }
 
-void OpusAudioDecoder::Stop() {
+OpusAudioDecoder::~OpusAudioDecoder() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   if (!opus_decoder_)
@@ -292,10 +292,6 @@ void OpusAudioDecoder::Stop() {
   CloseDecoder();
 }
 
-OpusAudioDecoder::~OpusAudioDecoder() {
-  DCHECK(!opus_decoder_);
-}
-
 void OpusAudioDecoder::DecodeBuffer(
     const scoped_refptr<DecoderBuffer>& input,
     const DecodeCB& decode_cb) {