Web MIDI backend for Windows 10

media/midi/midi_options.gni

Index: media/midi/midi_options.gni
diff --git a/media/midi/midi_options.gni b/media/midi/midi_options.gni
new file mode 100644
index 0000000000000000000000000000000000000000..2f1259682b2ad498f10c3aefc99bb0f4b6c89b01
--- /dev/null
+++ b/media/midi/midi_options.gni
@@ -0,0 +1,10 @@
+# Copyright 2016 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.
+
+declare_args() {
+  # Enables MIDI implementation using WinRT APIs on Windows 10.
+  # TODO(shaochuan): Switch to using a runtime flag to choose between
+  # implementations.
+  midi_use_winrt = false
+}