Add RetainedRef uses where needed.

chrome/browser/media_galleries/fileapi/mtp_file_stream_reader.cc

Index: chrome/browser/media_galleries/fileapi/mtp_file_stream_reader.cc
diff --git a/chrome/browser/media_galleries/fileapi/mtp_file_stream_reader.cc b/chrome/browser/media_galleries/fileapi/mtp_file_stream_reader.cc
index 8b728a999b3c5fb4914990d0f83a9278045cd0bf..eeba117953deb4867fb9b7410db861943c823406 100644
--- a/chrome/browser/media_galleries/fileapi/mtp_file_stream_reader.cc
+++ b/chrome/browser/media_galleries/fileapi/mtp_file_stream_reader.cc
@@ -103,17 +103,12 @@ int MTPFileStreamReader::Read(net::IOBuffer* buf, int buf_len,
       header_buf_len = net::kMaxBytesToSniff;
     }
 
-    ReadBytes(url_,
-              header_buf.get(),
-              0,
-              header_buf_len,
-              base::Bind(&MTPFileStreamReader::FinishValidateMediaHeader,
-                         weak_factory_.GetWeakPtr(),
-                         header_buf,
-                         make_scoped_refptr(buf),
-                         buf_len,
-                         callback),
-              callback);
+    ReadBytes(
+        url_, header_buf.get(), 0, header_buf_len,
+        base::Bind(&MTPFileStreamReader::FinishValidateMediaHeader,
+                   weak_factory_.GetWeakPtr(), base::RetainedRef(header_buf),
+                   base::RetainedRef(buf), buf_len, callback),
+        callback);
     return net::ERR_IO_PENDING;
   }