Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/formats/mp4/dolby_vision.cc

Index: media/formats/mp4/dolby_vision.cc
diff --git a/media/formats/mp4/dolby_vision.cc b/media/formats/mp4/dolby_vision.cc
index c40decdf28276deb3830a4c5fe4a49d0a0b7fad1..743fa9e38b9e230d527dd0fd10a40cf8a7210d0b 100644
--- a/media/formats/mp4/dolby_vision.cc
+++ b/media/formats/mp4/dolby_vision.cc
@@ -34,12 +34,13 @@ bool DolbyVisionConfiguration::Parse(BoxReader* reader) {
 
 bool DolbyVisionConfiguration::Parse(const uint8_t* data, int data_size) {
   BufferReader reader(data, data_size);
-  return ParseInternal(&reader, new MediaLog());
+  // TODO(wolenetz): Questionable MediaLog usage, http://crbug.com/712310
+  MediaLog media_log;
+  return ParseInternal(&reader, &media_log);
 }
 
-bool DolbyVisionConfiguration::ParseInternal(
-    BufferReader* reader,
-    const scoped_refptr<MediaLog>& media_log) {
+bool DolbyVisionConfiguration::ParseInternal(BufferReader* reader,
+                                             MediaLog* media_log) {
   uint16_t profile_track_indication = 0;
   RCHECK(reader->Read1(&dv_version_major) && reader->Read1(&dv_version_minor) &&
          reader->Read2(&profile_track_indication));