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 8552403024765aad2ceef1427bd516ea73c5ee52..d59f8576dd5a6fce0e61b20640cf97f019b71532 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, MidiPortState state) override {}
+
+  void SetOutputPortState(uint32 port_index, MidiPortState state) override {}
+
   void CompleteStartSession(MidiResult result) override {
     complete_start_session_ = true;
     result_ = result;