Web MIDI: move MIDI message validating logic into message_util.{cc|h}

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 <stddef.h>
-#include <stdint.h>
-
-#include <deque>
-#include <vector>
-
-#include "media/midi/midi_export.h"
-
-namespace midi {
-
-// 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.
-// - MIDI System Exclusive message.
-// - End of System Exclusive message.
-// - Reserved System Common Message (0xf4, 0xf5)
-MIDI_EXPORT size_t GetMidiMessageLength(uint8_t status_byte);
-
-const uint8_t kSysExByte = 0xf0;
-const uint8_t kEndOfSysExByte = 0xf7;
-
-const uint8_t kSysMessageBitMask = 0xf0;
-const uint8_t kSysMessageBitPattern = 0xf0;
-const uint8_t kSysRTMessageBitMask = 0xf8;
-const uint8_t kSysRTMessageBitPattern = 0xf8;
-
-}  // namespace midi
-
-#endif  // MEDIA_MIDI_MIDI_MESSAGE_UTIL_H_