Add a PermissionContext subclass for the midi permission

chrome/browser/media/midi_permission_context.cc

Index: chrome/browser/media/midi_permission_context.cc
diff --git a/chrome/browser/media/midi_permission_context.cc b/chrome/browser/media/midi_permission_context.cc
index 218f9b9599c5df2e68f07bc196972c0d765600f4..b4393b850b063437fc03d3e68f6c1302d06d030b 100644
--- a/chrome/browser/media/midi_permission_context.cc
+++ b/chrome/browser/media/midi_permission_context.cc
@@ -1,38 +1,20 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright 2017 The Chromium Authors. All rights reserved.

[Sergey Ulanov, 2017/05/25 18:41:22]

nit: copyright year doesn't need to be changed when you edit a file

[raymes, 2017/05/29 00:26:10]

Done.

 // 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 "chrome/browser/permissions/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) {}
+    : PermissionContextBase(profile, CONTENT_SETTINGS_TYPE_MIDI) {}
 
 MidiPermissionContext::~MidiPermissionContext() {
 }
 
-void MidiPermissionContext::UpdateTabContext(const PermissionRequestID& id,
-                                             const GURL& requesting_frame,
-                                             bool allowed) {
-  TabSpecificContentSettings* content_settings =
-      TabSpecificContentSettings::GetForFrame(id.render_process_id(),
-                                              id.render_frame_id());
-  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);
-  }
+ContentSetting MidiPermissionContext::GetPermissionStatusInternal(
+    content::RenderFrameHost* render_frame_host,
+    const GURL& requesting_origin,
+    const GURL& embedding_origin) const {
+  return CONTENT_SETTING_ALLOW;

[Sergey Ulanov, 2017/05/25 18:41:23]

Does this mean that MIDI permission is automatically granted to all pages that
request it? Is that what we want here?

[raymes, 2017/05/29 00:26:10]

Yes - that is what happens for MIDI today. We show a prompt for MIDI_SYSEX
though.

 }
 
 bool MidiPermissionContext::IsRestrictedToSecureOrigins() const {