Convert some audio code to OnceCallback.

content/browser/renderer_host/media/audio_output_authorization_handler.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_AUDIO_OUTPUT_AUTHORIZATION_HANDLER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_OUTPUT_AUTHORIZATION_HANDLER_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 18 matching lines @@
 // use the device, and gets the default device parameters for the selected audio
 // device.
 class CONTENT_EXPORT AudioOutputAuthorizationHandler {
  public:
   // The result of an authorization check. In addition to the status, it
   // indicates whether a device was found using the |session_id| in the variable
   // |should_send_id|, in which case the renderer expects to get the id hash. It
   // also has the default audio parameters for the device, and the id for the
   // device, which is needed to open a stream for the device. This id is not
   // hashed, so it must be hashed before sending it to the renderer.
-  // TODO(maxmorin): Change to OnceCallback once base:: code is ready for it.
   using AuthorizationCompletedCallback =
-      base::Callback<void(media::OutputDeviceStatus status,
-                          bool should_send_id,
-                          const media::AudioParameters& params,
-                          const std::string& raw_device_id)>;
+      base::OnceCallback<void(media::OutputDeviceStatus status,
+                              bool should_send_id,
+                              const media::AudioParameters& params,
+                              const std::string& raw_device_id)>;
 
   AudioOutputAuthorizationHandler(media::AudioSystem* audio_system,
                                   MediaStreamManager* media_stream_manager,
                                   int render_process_id_,
                                   const std::string& salt);
 
   ~AudioOutputAuthorizationHandler();
 
   // Checks authorization of the device with the hashed id |device_id| for the
   // given render frame id and security origin, or uses |session_id| for
@@ skipping 42 matching lines @@
   // const, so this can be mutable.
   mutable base::WeakPtrFactory<const AudioOutputAuthorizationHandler>
       weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputAuthorizationHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_OUTPUT_AUTHORIZATION_HANDLER_H_