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 84b3ac286fef2e6830bf72a7d594a874f6cf4e48..62784ddf71036fc4f97fb03d320049ebbb5ee372 100644
--- a/media/filters/opus_audio_decoder.cc
+++ b/media/filters/opus_audio_decoder.cc
@@ -282,7 +282,7 @@ 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_)
@@ -293,10 +293,6 @@ void OpusAudioDecoder::Stop() {
   CloseDecoder();
 }
 
-OpusAudioDecoder::~OpusAudioDecoder() {
-  DCHECK(!opus_decoder_);
-}
-
 void OpusAudioDecoder::DecodeBuffer(
     const scoped_refptr<DecoderBuffer>& input,
     const DecodeCB& decode_cb) {