Move audio output number limit to AudioManager.

media/audio/mac/audio_manager_mac.h

 // Copyright (c) 2010 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 "base/basictypes.h"
 #include "media/audio/audio_manager_base.h"
 
 class PCMQueueInAudioInputStream;
 class PCMQueueOutAudioOutputStream;
 
 // Mac OS X implementation of the AudioManager singleton. This class is internal
 // to the audio output and only internal users can call methods not exposed by
 // the AudioManager class.
 class AudioManagerMac : public AudioManagerBase {
  public:
-  AudioManagerMac() {};
+  AudioManagerMac();
 
   // Implementation of AudioManager.
   virtual bool HasAudioOutputDevices();
   virtual bool HasAudioInputDevices();
   virtual AudioOutputStream* MakeAudioOutputStream(AudioParameters params);
   virtual AudioInputStream* MakeAudioInputStream(AudioParameters params);
   virtual void MuteAll();
   virtual void UnMuteAll();
 
   // Mac-only method to free the streams created by above facoty methods.
   // They are called internally by the respective audio stream when it has
   // been closed.
   void ReleaseOutputStream(PCMQueueOutAudioOutputStream* stream);
   void ReleaseInputStream(PCMQueueInAudioInputStream* stream);
 
  private:
-  friend void DestroyAudioManagerMac(void*);
-  virtual ~AudioManagerMac() {};
+  virtual ~AudioManagerMac();
+
+  // Number of currently open output streams.
+  size_t num_output_streams_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioManagerMac);
 };
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_MANAGER_MAC_H_