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

media/midi/midi_message_util.h

 // Copyright 2013 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_MIDI_MESSAGE_UTIL_H_
 #define MEDIA_MIDI_MIDI_MESSAGE_UTIL_H_
 
 #include <deque>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // Returns the length of a MIDI message in bytes. Never returns 4 or greater.
 // Returns 0 if |status_byte| is:
 // - not a valid status byte, namely data byte.
 // - the MIDI System Exclusive message.
 // - the End of System Exclusive message.
 MEDIA_EXPORT size_t GetMIDIMessageLength(uint8 status_byte);
 
+const uint8 kSystemExclusiveByte = 0xf0;
+const uint8 kSystemExclusiveEndByte = 0xf7;
+const uint8 kSystemMessagePattern = 0xf0;

[Takashi Toyoshima, 2014/01/15 12:08:40]

Can you insert one line after the line 24, and how about renaming and adding
like this.

kMessageTypeMask = 0xf0;
kSystemMessageType = 0xf0;

[yhirano, 2014/01/15 13:25:42]

Done.

+
 }  // namespace media
 
 #endif  // MEDIA_MIDI_MIDI_MESSAGE_UTIL_H_