Add "use-winrt-midi-api" flag to enable WinRT WebMIDI backend

media/midi/midi_manager_win.cc

 // 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.
 
 #include "media/midi/midi_manager_win.h"
 
 #include <windows.h>
 #include <ks.h>
 #include <ksmedia.h>
 #include <mmreg.h>
 // Prevent unnecessary functions from being included from <mmsystem.h>
 #define MMNODRV
 #define MMNOSOUND
 #define MMNOWAVE
 #define MMNOAUX
 #define MMNOMIXER
 #define MMNOTIMER
 #define MMNOJOY
 #define MMNOMCI
 #define MMNOMMIO
 #include <mmsystem.h>
 #include <stddef.h>
 
 #include <algorithm>
 #include <functional>
 #include <queue>
 #include <string>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/system_monitor/system_monitor.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "base/win/message_window.h"
+#include "base/win/windows_version.h"
 #include "device/usb/usb_ids.h"
+#include "media/midi/midi_manager_winrt.h"
 #include "media/midi/midi_message_queue.h"
 #include "media/midi/midi_message_util.h"
 #include "media/midi/midi_port_info.h"
+#include "media/midi/midi_switches.h"
 
 namespace media {
 namespace midi {
 namespace {
 
 static const size_t kBufferLength = 32 * 1024;
 
 // We assume that nullpter represents an invalid MIDI handle.
 const HMIDIIN kInvalidMidiInHandle = nullptr;
 const HMIDIOUT kInvalidMidiOutHandle = nullptr;
@@ skipping 1125 matching lines @@
   SetOutputPortState(port_index, state);
 }
 
 void MidiManagerWin::OnReceiveMidiData(uint32_t port_index,
                                        const std::vector<uint8_t>& data,
                                        base::TimeTicks time) {
   ReceiveMidiData(port_index, &data[0], data.size(), time);
 }
 
 MidiManager* MidiManager::Create() {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kUseWinrtMidiApi) &&
+      base::win::GetVersion() >= base::win::VERSION_WIN10)
+    return new MidiManagerWinrt();
   return new MidiManagerWin();
 }
 
 }  // namespace midi
 }  // namespace media