Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/base/demuxer_perftest.cc

Index: media/base/demuxer_perftest.cc
diff --git a/media/base/demuxer_perftest.cc b/media/base/demuxer_perftest.cc
index b04db50b47e65cd30e295ae24f2249045a247ae0..4bfbaef61ecf8928e1d5e512e77f77991d1f7d78 100644
--- a/media/base/demuxer_perftest.cc
+++ b/media/base/demuxer_perftest.cc
@@ -178,6 +178,7 @@ int StreamReader::GetNextStreamIndexToRead() {
 static void RunDemuxerBenchmark(const std::string& filename) {
   base::FilePath file_path(GetTestDataFilePath(filename));
   base::TimeDelta total_time;
+  MediaLog media_log_;
   for (int i = 0; i < kBenchmarkIterations; ++i) {
     // Setup.
     base::test::ScopedTaskScheduler scoped_task_scheduler;
@@ -191,7 +192,7 @@ static void RunDemuxerBenchmark(const std::string& filename) {
         base::Bind(&OnMediaTracksUpdated);
     FFmpegDemuxer demuxer(base::ThreadTaskRunnerHandle::Get(), &data_source,
                           encrypted_media_init_data_cb, tracks_updated_cb,
-                          new MediaLog());
+                          &media_log_);
 
     {
       base::RunLoop run_loop;