Update MidiDispatcher to use Mojo Permission Service.

chrome/browser/media/midi_permission_context.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 "chrome/browser/media/midi_permission_context.h"
 
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "components/content_settings/core/common/permission_request_id.h"
+#include "content/public/browser/child_process_security_policy.h"
 #include "url/gurl.h"
 
 MidiPermissionContext::MidiPermissionContext(Profile* profile)
     : PermissionContextBase(profile, CONTENT_SETTINGS_TYPE_MIDI_SYSEX) {
 }
 
 MidiPermissionContext::~MidiPermissionContext() {
 }
 
 
 void MidiPermissionContext::UpdateTabContext(const PermissionRequestID& id,
                                              const GURL& requesting_frame,
                                              bool allowed) {
   TabSpecificContentSettings* content_settings =
       TabSpecificContentSettings::Get(id.render_process_id(),
                                       id.render_view_id());
-  if (content_settings) {
-    if (allowed)
-      content_settings->OnMidiSysExAccessed(requesting_frame);
-    else
-      content_settings->OnMidiSysExAccessBlocked(requesting_frame);
+  if (!content_settings)
+    return;
+
+  if (allowed) {
+    content_settings->OnMidiSysExAccessed(requesting_frame);
+
+    content::ChildProcessSecurityPolicy::GetInstance()->
+        GrantSendMidiSysExMessage(id.render_process_id());
+  } else {
+    content_settings->OnMidiSysExAccessBlocked(requesting_frame);
   }
 }