Stop playing/recording when not needed.

components/copresence/mediums/audio/audio_player.h

 // Copyright 2014 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 COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_PLAYER_
-#define COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_PLAYER_
+#ifndef COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_PLAYER_H_
+#define COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_PLAYER_H_
 
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "media/audio/audio_io.h"
 
 namespace media {
 class AudioBus;
 class AudioBusRefCounted;
 }
 
 namespace copresence {
 
 // The AudioPlayer class will play a set of samples till it is told to stop.
 class AudioPlayer : public media::AudioOutputStream::AudioSourceCallback {
  public:
   AudioPlayer();
 
   // Initializes the object. Do not use this object before calling this method.
-  void Initialize();
+  virtual void Initialize();
 
   // Play the given samples. These samples will keep on being played in a loop
   // till we explicitly tell the player to stop playing.
-  void Play(const scoped_refptr<media::AudioBusRefCounted>& samples);
+  virtual void Play(const scoped_refptr<media::AudioBusRefCounted>& samples);
 
   // Stop playing.
-  void Stop();
+  virtual void Stop();
+
+  virtual bool IsPlaying();

[xiyuan, 2014/08/12 18:57:50]

nit: Make it a non-virtual accessor?

[rkc, 2014/08/13 00:29:00]

Done.

 
   // Cleans up and deletes this object. Do not use object after this call.
-  void Finalize();
+  virtual void Finalize();
 
   // Takes ownership of the stream.
   void set_output_stream_for_testing(
       media::AudioOutputStream* output_stream_for_testing) {
     output_stream_for_testing_.reset(output_stream_for_testing);
   }
 
+ protected:
+  virtual ~AudioPlayer();
+
+  bool is_playing_;

[xiyuan, 2014/08/12 18:57:50]

nit: prefer to have protected setter accessor than promoting a member var into
protected.

[rkc, 2014/08/13 00:29:00]

Done.

+
  private:
   friend class AudioPlayerTest;
   FRIEND_TEST_ALL_PREFIXES(AudioPlayerTest, BasicPlayAndStop);
   FRIEND_TEST_ALL_PREFIXES(AudioPlayerTest, OutOfOrderPlayAndStopMultiple);
 
-  virtual ~AudioPlayer();
-
   // Methods to do our various operations; all of these need to be run on the
   // audio thread.
   void InitializeOnAudioThread();
   void PlayOnAudioThread(
       const scoped_refptr<media::AudioBusRefCounted>& samples);
   void StopOnAudioThread();
   void StopAndCloseOnAudioThread();
   void FinalizeOnAudioThread();
 
   // AudioOutputStream::AudioSourceCallback overrides:
   // Following methods could be called from *ANY* thread.
   virtual int OnMoreData(media::AudioBus* dest,
                          media::AudioBuffersState /* state */) OVERRIDE;
   virtual void OnError(media::AudioOutputStream* /* stream */) OVERRIDE;
 
   // Flushes the audio loop, making sure that any queued operations are
   // performed.
   void FlushAudioLoopForTesting();
 
   // Self-deleting object.
   media::AudioOutputStream* stream_;
 
   scoped_ptr<media::AudioOutputStream> output_stream_for_testing_;
 
-  bool is_playing_;
-
   // All fields below here are protected by this lock.
   base::Lock state_lock_;
 
   scoped_refptr<media::AudioBusRefCounted> samples_;
 
   // Index to the frame in the samples that we need to play next.
   int frame_index_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioPlayer);
 };
 
 }  // namespace copresence
 
-#endif  // COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_PLAYER_
+#endif  // COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_PLAYER_H_