Web MIDI: use midi_service.mojom for media::midi::Result

media/midi/BUILD.gn

Index: media/midi/BUILD.gn
diff --git a/media/midi/BUILD.gn b/media/midi/BUILD.gn
index b7479365c5c5cd33d72a912674999d32bec76daf..3f860a4f3cd627553c6cc42d38e64412ab3d3994 100644
--- a/media/midi/BUILD.gn
+++ b/media/midi/BUILD.gn
@@ -6,6 +6,7 @@ import("//build/config/android/config.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//media/media_options.gni")
+import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
 if (is_android) {
@@ -95,6 +96,7 @@ component("midi") {
 
   defines = [ "MIDI_IMPLEMENTATION" ]
   deps = [
+    ":mojo",
     "//base",
   ]
   libs = []
@@ -167,6 +169,13 @@ component("midi") {
   }
 }
 
+mojom("mojo") {
+  sources = [
+    "midi_service.mojom",
+  ]
+  use_new_wrapper_types = true
+}
+
 test("midi_unittests") {
   sources = [
     "midi_manager_unittest.cc",