Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/filters/decrypting_video_decoder.h

Index: media/filters/decrypting_video_decoder.h
diff --git a/media/filters/decrypting_video_decoder.h b/media/filters/decrypting_video_decoder.h
index cd3549ced23cffef95481670bc4b5d657f146ba0..034ec943e3d93d922162b12b41998cdcb84414d2 100644
--- a/media/filters/decrypting_video_decoder.h
+++ b/media/filters/decrypting_video_decoder.h
@@ -33,7 +33,7 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
  public:
   DecryptingVideoDecoder(
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
-      const scoped_refptr<MediaLog>& media_log,
+      MediaLog* media_log,
       const base::Closure& waiting_for_decryption_key_cb);
   ~DecryptingVideoDecoder() override;
 
@@ -83,7 +83,7 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
-  scoped_refptr<MediaLog> media_log_;
+  MediaLog* media_log_;
 
   State state_;