Fix race in MediaDevicesPermissionChecker.

content/browser/renderer_host/media/media_devices_dispatcher_host.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_DEVICES_DISPATCHER_HOST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_DEVICES_DISPATCHER_HOST_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 30 matching lines @@
 
   // ::mojom::MediaDevicesDispatcherHost implementation.
   void EnumerateDevices(
       bool request_audio_input,
       bool request_video_input,
       bool request_audio_output,
       const url::Origin& security_origin,
       const EnumerateDevicesCallback& client_callback) override;
 
   void SetPermissionChecker(
-      const MediaDevicesPermissionChecker& permission_checker);
+      std::unique_ptr<MediaDevicesPermissionChecker> permission_checker);
 
  private:
   void DoEnumerateDevices(
       const MediaDevicesManager::BoolDeviceTypes& requested_types,
       const url::Origin& security_origin,
       const EnumerateDevicesCallback& client_callback,
       const MediaDevicesManager::BoolDeviceTypes& permissions);
 
   void DevicesEnumerated(
       const MediaDevicesManager::BoolDeviceTypes& requested_types,
       const url::Origin& security_origin,
       const EnumerateDevicesCallback& client_callback,
       const MediaDevicesManager::BoolDeviceTypes& has_permissions,
       const MediaDeviceEnumeration& enumeration);
 
   int render_process_id_;
   int routing_id_;
   std::string device_id_salt_;
   std::string group_id_salt_;
   MediaStreamManager* media_stream_manager_;
-  MediaDevicesPermissionChecker permission_checker_;
+  std::unique_ptr<MediaDevicesPermissionChecker> permission_checker_;
 
   base::WeakPtrFactory<MediaDevicesDispatcherHost> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaDevicesDispatcherHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_DEVICES_DISPATCHER_HOST_H_