Web MIDI: convert Android native API switch to a field trial

media/midi/midi_switches.h

 // Copyright 2015 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.
 
 // Defines all the "midi" command-line switches.
 
 #ifndef MEDIA_MIDI_MIDI_SWITCHES_H_
 #define MEDIA_MIDI_MIDI_SWITCHES_H_
 
 #include "base/feature_list.h"
 #include "build/build_config.h"
 #include "media/midi/midi_export.h"
 
-namespace switches {
-
-#if defined(OS_ANDROID)
-MIDI_EXPORT extern const char kUseAndroidMidiApi[];
-#endif
-
-}  // namespace switches
-
 namespace midi {
 namespace features {
 
+#if defined(OS_ANDROID)
+MIDI_EXPORT extern const base::Feature kMidiManagerAndroid;
+#endif
+
 #if defined(OS_WIN)
 MIDI_EXPORT extern const base::Feature kMidiManagerWinrt;
 #endif
 
 }  // namespace features
 }  // namespace midi
 
 #endif  // MEDIA_MIDI_MIDI_SWITCHES_H_