Tab Audio Mirroring: WebContentsAudioInputStream is a new implementation which represents the lifet…

media/audio/virtual_audio_input_stream.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_VIRTUAL_AUDIO_INPUT_STREAM_H_
 #define MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_
 
 #include <map>
 #include <set>
 
 #include "base/cancelable_callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "media/audio/audio_io.h"
-#include "media/audio/audio_manager_base.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/audio_converter.h"
 
+namespace base {
+class MessageLoopProxy;
+}
+
 namespace media {
 
 class LoopbackAudioConverter;
 class VirtualAudioOutputStream;
 
 // VirtualAudioInputStream converts and mixes audio from attached
 // VirtualAudioOutputStreams into a single stream. It will continuously render
 // audio until this VirtualAudioInputStream is stopped and closed.
 class MEDIA_EXPORT VirtualAudioInputStream : public AudioInputStream {
  public:
-  static VirtualAudioInputStream* MakeStream(
-      AudioManagerBase* manager,
-      const AudioParameters& params,
-      base::MessageLoopProxy* message_loop);
+  // Callback invoked just after VirtualAudioInputStream is closed.
+  typedef base::Callback<void(VirtualAudioInputStream* vais)>
+      AfterCloseCallback;
+
+  // Construct a target for audio loopback which mixes multiple data streams
+  // into a single stream having the given |params|.
+  VirtualAudioInputStream(const AudioParameters& params,
+                          base::MessageLoopProxy* message_loop,
+                          const AfterCloseCallback& after_close_cb);
 
   virtual ~VirtualAudioInputStream();
 
   // AudioInputStream:
   virtual bool Open() OVERRIDE;
   virtual void Start(AudioInputCallback* callback) OVERRIDE;
   virtual void Stop() OVERRIDE;
   virtual void Close() OVERRIDE;
   virtual double GetMaxVolume() OVERRIDE;
   virtual void SetVolume(double volume) OVERRIDE;
   virtual double GetVolume() OVERRIDE;
   virtual void SetAutomaticGainControl(bool enabled) OVERRIDE;
   virtual bool GetAutomaticGainControl() OVERRIDE;
 
   // Attaches a VirtualAudioOutputStream to be used as input. This
   // VirtualAudioInputStream must outlive all attached streams, so any attached
   // stream must be closed (which causes a detach) before
   // VirtualAudioInputStream is destroyed.
   virtual void AddOutputStream(VirtualAudioOutputStream* stream,
                                const AudioParameters& output_params);
 
   // Detaches a VirtualAudioOutputStream and removes it as input.
   virtual void RemoveOutputStream(VirtualAudioOutputStream* stream,
                                   const AudioParameters& output_params);
 
- protected:
+ private:
   friend class VirtualAudioInputStreamTest;
-  FRIEND_TEST_ALL_PREFIXES(AudioOutputControllerTest,
-                           VirtualStreamsTriggerDeviceChange);
 
   typedef std::map<AudioParameters, LoopbackAudioConverter*> AudioConvertersMap;
 
-  VirtualAudioInputStream(AudioManagerBase* manager,
-                          const AudioParameters& params,
-                          base::MessageLoopProxy* message_loop);
-
   // When Start() is called on this class, we continuously schedule this
   // callback to render audio using any attached VirtualAudioOutputStreams until
   // Stop() is called.
   void ReadAudio();
 
-  AudioManagerBase* audio_manager_;
-  base::MessageLoopProxy* message_loop_;
+  base::MessageLoopProxy* const message_loop_;
+
+  AfterCloseCallback after_close_cb_;
+
   AudioInputCallback* callback_;
 
   // Non-const for testing.
   base::TimeDelta buffer_duration_;
   base::Time next_read_time_;
   scoped_array<uint8> buffer_;
   AudioParameters params_;
   scoped_ptr<AudioBus> audio_bus_;
   base::CancelableClosure on_more_data_cb_;
 
   // AudioConverters associated with the attached VirtualAudioOutputStreams,
   // partitioned by common AudioParameters.
   AudioConvertersMap converters_;
 
   // AudioConverter that takes all the audio converters and mixes them into one
   // final audio stream.
   AudioConverter mixer_;
 
   // Number of currently attached VirtualAudioOutputStreams.
-  int num_attached_outputs_streams_;
+  int num_attached_output_streams_;
 
   DISALLOW_COPY_AND_ASSIGN(VirtualAudioInputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_