Remove unnecessary casts in AudioManagerDeleter on Mac.

media/audio/mac/audio_manager_mac.h

 // Copyright (c) 2012 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 MEDIA_AUDIO_MAC_AUDIO_MANAGER_MAC_H_
 #define MEDIA_AUDIO_MAC_AUDIO_MANAGER_MAC_H_
 
 #include <AudioUnit/AudioUnit.h>
 #include <CoreAudio/AudioHardware.h>
 #include <stddef.h>
@@ skipping 107 matching lines @@
                              size_t* io_buffer_frame_size);
 
   // Number of constructed output and input streams.
   size_t output_streams() const { return output_streams_.size(); }
   size_t low_latency_input_streams() const {
     return low_latency_input_streams_.size();
   }
   size_t basic_input_streams() const { return basic_input_streams_.size(); }
 
  protected:
-  friend class media::AudioManagerDeleter;
-
   ~AudioManagerMac() override;
   AudioParameters GetPreferredOutputStreamParameters(
       const std::string& output_device_id,
       const AudioParameters& input_params) override;
 
  private:
   void InitializeOnAudioThread();
 
   int ChooseBufferSize(bool is_input, int sample_rate);
 
@@ skipping 48 matching lines @@
   // Set to true in the destructor. Ensures that methods that touches native
   // Core Audio APIs are not executed during shutdown.
   bool in_shutdown_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerMac);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_MANAGER_MAC_H_