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

chrome/browser/about_flags.cc

 // Copyright (c) 2012 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 "chrome/browser/about_flags.h"
 
 #include <iterator>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 1712 matching lines @@
      SINGLE_VALUE_TYPE(switches::kUseAndroidMidiApi)},
 #endif  // defined(OS_ANDROID)
 #if defined(OS_WIN)
     {"trace-export-events-to-etw", IDS_FLAGS_TRACE_EXPORT_EVENTS_TO_ETW_NAME,
      IDS_FLAGS_TRACE_EXPORT_EVENTS_TO_ETW_DESRIPTION, kOsWin,
      SINGLE_VALUE_TYPE(switches::kTraceExportEventsToETW)},
     {"merge-key-char-events", IDS_FLAGS_MERGE_KEY_CHAR_EVENTS_NAME,
      IDS_FLAGS_MERGE_KEY_CHAR_EVENTS_DESCRIPTION, kOsWin,
      ENABLE_DISABLE_VALUE_TYPE(switches::kEnableMergeKeyCharEvents,
                                switches::kDisableMergeKeyCharEvents)},
+    {"use-winrt-midi-api", IDS_FLAGS_USE_WINRT_MIDI_API_NAME,
+     IDS_FLAGS_USE_WINRT_MIDI_API_DESCRIPTION, kOsWin,
+     SINGLE_VALUE_TYPE(switches::kUseWinrtMidiApi)},
 #endif  // defined(OS_WIN)
 #if BUILDFLAG(ENABLE_BACKGROUND)
     {"enable-push-api-background-mode", IDS_FLAGS_PUSH_API_BACKGROUND_MODE_NAME,
      IDS_FLAGS_PUSH_API_BACKGROUND_MODE_DESCRIPTION, kOsMac | kOsWin | kOsLinux,
      ENABLE_DISABLE_VALUE_TYPE(switches::kEnablePushApiBackgroundMode,
                                switches::kDisablePushApiBackgroundMode)},
 #endif  // BUILDFLAG(ENABLE_BACKGROUND)
 #if defined(OS_CHROMEOS)
     {"cros-regions-mode", IDS_FLAGS_CROS_REGIONS_MODE_NAME,
      IDS_FLAGS_CROS_REGIONS_MODE_DESCRIPTION, kOsCrOS,
@@ skipping 483 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags