Web MIDI: make MidiManagerMac notify device connections

media/midi/midi_manager_usb_unittest.cc

Index: media/midi/midi_manager_usb_unittest.cc
diff --git a/media/midi/midi_manager_usb_unittest.cc b/media/midi/midi_manager_usb_unittest.cc
index 5fbaa1b7b6718f83ad905156af4fc8a1f1423e10..5d41504c6779a446f3d11e02a8ff74d91d11c0d7 100644
--- a/media/midi/midi_manager_usb_unittest.cc
+++ b/media/midi/midi_manager_usb_unittest.cc
@@ -86,6 +86,10 @@ class FakeMidiManagerClient : public MidiManagerClient {
     output_ports_.push_back(info);
   }
 
+  void SetInputPortState(uint32 port_index, bool connected) override {}
+
+  void SetOutputPortState(uint32 port_index, bool connected) override {}
+
   void CompleteStartSession(MidiResult result) override {
     complete_start_session_ = true;
     result_ = result;