Add toyoshim as a per-file owner for Web MIDI

NOTRY=true

Review URL: https://codereview.chromium.org/663823004

Cr-Commit-Position: refs/heads/master@{#300325}

content/browser/media/OWNERS

@@ -12,5 +12,7 @@ per-file cast_*=hubbe@chromium.org
 per-file cast_*=mikhal@chromium.org
 per-file cast_*=pwestin@google.com
 
+per-file midi_*=toyoshim@chromium.org
+
 # For changes related to the tab media indicators.
 per-file audio_stream_monitor*=miu@chromium.org

content/renderer/media/OWNERS

@@ -12,3 +12,6 @@ per-file cast_*=hclam@chromium.org
 per-file cast_*=hubbe@chromium.org
 per-file cast_*=mikhal@chromium.org
 per-file cast_*=pwestin@google.com
+
+per-file midi_*=toyoshim@chromium.org
+per-file renderer_webmidi*=toyoshim@chromium.org