Replace scoped_ptr with std::unique_ptr in //media.

media/midi/midi_manager_win.cc

Index: media/midi/midi_manager_win.cc
diff --git a/media/midi/midi_manager_win.cc b/media/midi/midi_manager_win.cc
index 43900243f4202a0cb1a197f253b6c1f0a98930bb..610aa4f22eb484c2c0c263c5d2be90e15e6fbfb8 100644
--- a/media/midi/midi_manager_win.cc
+++ b/media/midi/midi_manager_win.cc
@@ -94,7 +94,7 @@ class MIDIHDRDeleter {
   }
 };
 
-typedef scoped_ptr<MIDIHDR, MIDIHDRDeleter> ScopedMIDIHDR;
+using ScopedMIDIHDR = std::unique_ptr<MIDIHDR, MIDIHDRDeleter>;
 
 ScopedMIDIHDR CreateMIDIHDR(size_t size) {
   ScopedMIDIHDR header(new MIDIHDR);