Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/filters/decoder_stream_traits.cc

Index: media/filters/decoder_stream_traits.cc
diff --git a/media/filters/decoder_stream_traits.cc b/media/filters/decoder_stream_traits.cc
index a578f400afbfc34f4d2b1782a39a4403451f4a8e..68b1b1a52aa3f9463d712c4bb87479751fe13385 100644
--- a/media/filters/decoder_stream_traits.cc
+++ b/media/filters/decoder_stream_traits.cc
@@ -43,7 +43,7 @@ DecoderStreamTraits<DemuxerStream::AUDIO>::GetDecoderConfig(
 }
 
 DecoderStreamTraits<DemuxerStream::AUDIO>::DecoderStreamTraits(
-    const scoped_refptr<MediaLog>& media_log)
+    MediaLog* media_log)
     : media_log_(media_log) {}
 
 void DecoderStreamTraits<DemuxerStream::AUDIO>::ReportStatistics(
@@ -111,7 +111,7 @@ DecoderStreamTraits<DemuxerStream::VIDEO>::GetDecoderConfig(
 }
 
 DecoderStreamTraits<DemuxerStream::VIDEO>::DecoderStreamTraits(
-    const scoped_refptr<MediaLog>& media_log)
+    MediaLog* media_log)
     // Randomly selected number of samples to keep.
     : keyframe_distance_average_(16) {}