Web MIDI: add dynamic MidiManager instantiation support for Linux

media/midi/midi_manager_android.h

Index: media/midi/midi_manager_android.h
diff --git a/media/midi/midi_manager_android.h b/media/midi/midi_manager_android.h
index 77ddf28ca2558a85e3258ab258b8873138cb56e2..fa29a441dbbf6adde817b34b14fa4193869ef17c 100644
--- a/media/midi/midi_manager_android.h
+++ b/media/midi/midi_manager_android.h
@@ -25,13 +25,14 @@ namespace midi {
 
 class MidiDeviceAndroid;
 class MidiOutputPortAndroid;
+class MidiService;
 
 // MidiManagerAndroid is a MidiManager subclass for Android M or newer. For
 // older android OSes, we use MidiManagerUsb.
 class MidiManagerAndroid final : public MidiManager,
                                  public MidiInputPortAndroid::Delegate {
  public:
-  MidiManagerAndroid();
+  explicit MidiManagerAndroid(MidiService* service);
   ~MidiManagerAndroid() override;
 
   // MidiManager implementation.