Remove reference counting from media::DemuxerStream and friends.

media/filters/ffmpeg_video_decoder.cc

Index: media/filters/ffmpeg_video_decoder.cc
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index bd7928ca5cc6474003663f4c4863ba4f557c9039..e853c0f5b1eb0f65cd9915747da1a43f536d7dbd 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -61,7 +61,8 @@ FFmpegVideoDecoder::FFmpegVideoDecoder(
       weak_factory_(this),
       state_(kUninitialized),
       codec_context_(NULL),
-      av_frame_(NULL) {
+      av_frame_(NULL),
+      demuxer_stream_(NULL) {
 }
 
 int FFmpegVideoDecoder::GetVideoBuffer(AVCodecContext* codec_context,
@@ -130,7 +131,7 @@ static void ReleaseVideoBufferImpl(AVCodecContext* s, AVFrame* frame) {
   frame->opaque = NULL;
 }
 
-void FFmpegVideoDecoder::Initialize(const scoped_refptr<DemuxerStream>& stream,
+void FFmpegVideoDecoder::Initialize(DemuxerStream* stream,
                                     const PipelineStatusCB& status_cb,
                                     const StatisticsCB& statistics_cb) {
   DCHECK(message_loop_->BelongsToCurrentThread());