[WebMIDI] Introduce UsbMidi{Input, Output}Stream.

media/midi/usb_midi_device.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_MIDI_USB_MIDI_DEVICE_H_
+#define MEDIA_MIDI_USB_MIDI_DEVICE_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+// UsbMidiDevice represents a USB-MIDI device.
+// This is an interface class and each platform-dependent implementation class
+// will be a derived class.
+class MEDIA_EXPORT UsbMidiDevice {
+ public:
+  virtual ~UsbMidiDevice() {}
+
+  // Returns the descriptor of this device.
+  virtual std::vector<uint8> GetDescriptor() = 0;
+
+  // Sends |data| to the given USB endpoint of this device.
+  virtual void Send(int endpoint_number, const std::vector<uint8>& data) = 0;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_MIDI_USB_MIDI_DEVICE_H_