[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 "base/callback.h"
+#include "base/memory/scoped_vector.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class MEDIA_EXPORT UsbMidiDeviceDelegate {

[scherkus (not reviewing), 2014/01/16 21:55:52]

I don't see this class being used anywhere -- can we remove it?

[yhirano, 2014/01/20 09:12:19]

Done.

+ public:
+  virtual ~UsbMidiDeviceDelegate() {}
+  virtual void ReceiveUsbMidiData(int endpoint_number,
+                                  const uint8* data,
+                                  size_t size,
+                                  double timestamp) = 0;
+};
+
+class MEDIA_EXPORT UsbMidiDevice {

[scherkus (not reviewing), 2014/01/16 21:55:52]

class needs docs

[yhirano, 2014/01/20 09:12:19]

Done.

+ public:
+  typedef ScopedVector<UsbMidiDevice> Devices;
+  class Factory {

[scherkus (not reviewing), 2014/01/16 21:55:52]

I don't see Factory being used anywhere

In general I advocate for not checking in code that isn't used, otherwise it can
tend to stick around unnoticed (not to mention it makes it harder to review
since there is no calling code)

If this CL can land w/o Factory being included I'd go ahead and remove it.

[yhirano, 2014/01/20 09:12:19]

Done.

+   public:
+    typedef base::Callback<void(bool result, Devices* devices)> Callback;
+    virtual ~Factory() {}
+    // Enumerates devices.
+    // Devices that have no USB-MIDI interfaces can be omitted.
+    // When the operation succeeds, |callback| will be called with |true| and
+    // devices.
+    // Otherwise |callback| will be called with |false| and an 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 ~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_