Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/filters/source_buffer_state.h

Index: media/filters/source_buffer_state.h
diff --git a/media/filters/source_buffer_state.h b/media/filters/source_buffer_state.h
index 81d50596e4418583f314d020c465e948ccf211de..ddad2f7cc39ee5631ccfbbc3c5e3099daf345453 100644
--- a/media/filters/source_buffer_state.h
+++ b/media/filters/source_buffer_state.h
@@ -39,7 +39,7 @@ class MEDIA_EXPORT SourceBufferState {
   SourceBufferState(std::unique_ptr<StreamParser> stream_parser,
                     std::unique_ptr<FrameProcessor> frame_processor,
                     const CreateDemuxerStreamCB& create_demuxer_stream_cb,
-                    const scoped_refptr<MediaLog>& media_log);
+                    MediaLog* media_log);
 
   ~SourceBufferState();
 
@@ -209,7 +209,7 @@ class MEDIA_EXPORT SourceBufferState {
   DemuxerStreamMap text_streams_;
 
   std::unique_ptr<FrameProcessor> frame_processor_;
-  scoped_refptr<MediaLog> media_log_;
+  MediaLog* media_log_;
   StreamParser::InitCB init_cb_;
 
   State state_;