Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/filters/decoder_stream_traits.h

Index: media/filters/decoder_stream_traits.h
diff --git a/media/filters/decoder_stream_traits.h b/media/filters/decoder_stream_traits.h
index e00de2f22e2012c4c02ad65d08aceb9c9d14f79a..e84e37dac39eb22c6d528761668ba9e7ee6a67e4 100644
--- a/media/filters/decoder_stream_traits.h
+++ b/media/filters/decoder_stream_traits.h
@@ -44,7 +44,7 @@ class MEDIA_EXPORT DecoderStreamTraits<DemuxerStream::AUDIO> {
   static scoped_refptr<OutputType> CreateEOSOutput();
   static DecoderConfigType GetDecoderConfig(DemuxerStream* stream);
 
-  explicit DecoderStreamTraits(const scoped_refptr<MediaLog>& media_log);
+  explicit DecoderStreamTraits(MediaLog* media_log);
 
   void ReportStatistics(const StatisticsCB& statistics_cb, int bytes_decoded);
   void InitializeDecoder(DecoderType* decoder,
@@ -63,7 +63,7 @@ class MEDIA_EXPORT DecoderStreamTraits<DemuxerStream::AUDIO> {
   // drift.
   std::unique_ptr<AudioTimestampValidator> audio_ts_validator_;
 
-  scoped_refptr<MediaLog> media_log_;
+  MediaLog* media_log_;
 };
 
 template <>
@@ -81,7 +81,7 @@ class MEDIA_EXPORT DecoderStreamTraits<DemuxerStream::VIDEO> {
   static scoped_refptr<OutputType> CreateEOSOutput();
   static DecoderConfigType GetDecoderConfig(DemuxerStream* stream);
 
-  explicit DecoderStreamTraits(const scoped_refptr<MediaLog>& media_log);
+  explicit DecoderStreamTraits(MediaLog* media_log);
 
   void ReportStatistics(const StatisticsCB& statistics_cb, int bytes_decoded);
   void InitializeDecoder(DecoderType* decoder,