[WebMIDI] Introduce MidiManagerUsb

media/midi/usb_midi_device.h

Index: media/midi/usb_midi_device.h
diff --git a/media/midi/usb_midi_device.h b/media/midi/usb_midi_device.h
index 3ff4481932ffade85ba894e3fb32c5bb8164b3f5..1d9ebc1618a7752e8813cb36f0fcb3d1afbf0fbd 100644
--- a/media/midi/usb_midi_device.h
+++ b/media/midi/usb_midi_device.h
@@ -14,10 +14,13 @@
 
 namespace media {
 
+class UsbMidiDevice;
+
 class MEDIA_EXPORT UsbMidiDeviceDelegate {
  public:
   virtual ~UsbMidiDeviceDelegate() {}
-  virtual void ReceiveUsbMidiData(int endpoint_number,
+  virtual void ReceiveUsbMidiData(UsbMidiDevice* device,
+                                  int endpoint_number,
                                   const uint8* data,
                                   size_t size,
                                   double timestamp) = 0;
@@ -37,7 +40,8 @@ class MEDIA_EXPORT UsbMidiDevice {
     // Otherwise |callback| will be called with |false| and empty devices.
     // When this factory is destroyed during the operation, the operation
     // will be canceled silently (i.e. |callback| will not be called).
-    virtual void EnumerateDevices(Callback callback) = 0;
+    virtual void EnumerateDevices(UsbMidiDeviceDelegate* delegate,
+                                  Callback callback) = 0;
   };
 
   virtual ~UsbMidiDevice() {}