Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/formats/webm/webm_cluster_parser.h

Index: media/formats/webm/webm_cluster_parser.h
diff --git a/media/formats/webm/webm_cluster_parser.h b/media/formats/webm/webm_cluster_parser.h
index 4fd9d843b9b5ce0960d4575befac0d2248012689..03ac73ddfb1e6be87c37690798908ff2e76a0e32 100644
--- a/media/formats/webm/webm_cluster_parser.h
+++ b/media/formats/webm/webm_cluster_parser.h
@@ -54,7 +54,7 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
     Track(int track_num,
           bool is_video,
           base::TimeDelta default_duration,
-          const scoped_refptr<MediaLog>& media_log);
+          MediaLog* media_log);
     Track(const Track& other);
     ~Track();
 
@@ -141,7 +141,7 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
     // splicing when these estimates are observed in SourceBufferStream.
     base::TimeDelta estimated_next_frame_duration_;
 
-    scoped_refptr<MediaLog> media_log_;
+    MediaLog* media_log_;
   };
 
   typedef std::map<int, Track> TextTrackMap;
@@ -157,7 +157,7 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
                     const std::string& audio_encryption_key_id,
                     const std::string& video_encryption_key_id,
                     const AudioCodec audio_codec,
-                    const scoped_refptr<MediaLog>& media_log);
+                    MediaLog* media_log);
   ~WebMClusterParser() override;
 
   // Resets the parser state so it can accept a new cluster.
@@ -315,7 +315,7 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
   // kInfiniteDuration if no buffers are currently missing duration.
   DecodeTimestamp ready_buffer_upper_bound_;
 
-  scoped_refptr<MediaLog> media_log_;
+  MediaLog* media_log_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(WebMClusterParser);
 };