Web MIDI: add a new UMA entry for the final result code

media/midi/midi_result.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef MEDIA_MIDI_MIDI_RESULT_H_
-#define MEDIA_MIDI_MIDI_RESULT_H_
-
-namespace media {
-namespace midi {
-
-// Result codes for MIDI.
-enum MidiResult {
-  MIDI_NOT_INITIALIZED = -1,
-  MIDI_OK = 0,
-  MIDI_NOT_SUPPORTED,
-  MIDI_INITIALIZATION_ERROR,
-
-  // |MIDI_RESULT_LAST| is used in content/common/media/midi_messages.h with
-  // IPC_ENUM_TRAITS_MAX_VALUE macro. Keep the value up to date. Otherwise
-  // a new value can not be passed to the renderer.
-  MIDI_RESULT_LAST = MIDI_INITIALIZATION_ERROR,
-};
-
-}  // namespace midi
-}  // namespace media
-
-#endif  // MEDIA_MIDI_MIDI_RESULT_H_