Convert MediaLog from being ref counted to owned by WebMediaPlayer.

testing/libfuzzer/fuzzers/mp4_box_reader_fuzzer.cc

Index: testing/libfuzzer/fuzzers/mp4_box_reader_fuzzer.cc
diff --git a/testing/libfuzzer/fuzzers/mp4_box_reader_fuzzer.cc b/testing/libfuzzer/fuzzers/mp4_box_reader_fuzzer.cc
index 6e5c6bd58a19cbc11f4732a8a9f5be012788d6b9..bd003022400ec251e2e889539017c97712b1cb3d 100644
--- a/testing/libfuzzer/fuzzers/mp4_box_reader_fuzzer.cc
+++ b/testing/libfuzzer/fuzzers/mp4_box_reader_fuzzer.cc
@@ -7,8 +7,8 @@
 
 #include <memory>
 
-#include "media/formats/mp4/box_reader.h"
 #include "base/logging.h"
+#include "media/formats/mp4/box_reader.h"
 
 class NullMediaLog : public media::MediaLog {
  public:
@@ -28,10 +28,10 @@ class NullMediaLog : public media::MediaLog {
 // Entry point for LibFuzzer.
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   bool err;
-  scoped_refptr<NullMediaLog> media_log(new NullMediaLog());
+  NullMediaLog media_log;
   std::unique_ptr<media::mp4::BoxReader> reader(
       media::mp4::BoxReader::ReadTopLevelBox(data, static_cast<const int>(size),
-                                             media_log, &err));
+                                             &media_log, &err));
   if (err) {
     return 0;
   }