Web MIDI: make input_ports_ and output_ports_ members private

media/midi/midi_manager.cc

Index: media/midi/midi_manager.cc
diff --git a/media/midi/midi_manager.cc b/media/midi/midi_manager.cc
index 6d6bda40751724a747f751d33f847c2d8fd63418..b98b9aca03b976f90ae1dfbecb22e3bc0f5a3914 100644
--- a/media/midi/midi_manager.cc
+++ b/media/midi/midi_manager.cc
@@ -103,6 +103,11 @@ void MidiManager::AddOutputPort(const MidiPortInfo& info) {
   output_ports_.push_back(info);
 }
 
+void MidiManager::ClearInputOutputPorts() {
+  input_ports_.clear();
+  output_ports_.clear();
+}
+
 void MidiManager::ReceiveMidiData(
     uint32 port_index,
     const uint8* data,