Move some generic functions to AudioManagerBase to be inherited by platform-specific AudioManager***

media/audio/audio_manager_base.h

Index: media/audio/audio_manager_base.h
diff --git a/media/audio/audio_manager_base.h b/media/audio/audio_manager_base.h
index 7f42ea70d81a7c4c9fd1d43bfff192eb6ba36191..1c1c098996ddcaec65d038ee3f8e748edcb2cdc3 100644
--- a/media/audio/audio_manager_base.h
+++ b/media/audio/audio_manager_base.h
@@ -38,14 +38,24 @@ class MEDIA_EXPORT AudioManagerBase : public AudioManager {
   virtual bool CanShowAudioInputSettings() OVERRIDE;
   virtual void ShowAudioInputSettings() OVERRIDE;
 
-  virtual void GetAudioInputDeviceNames(media::AudioDeviceNames* device_names)
-      OVERRIDE;
+  virtual void GetAudioInputDeviceNames(
+      media::AudioDeviceNames* device_names) OVERRIDE;
+
+  virtual AudioOutputStream* MakeAudioOutputStream(
+      const AudioParameters& params) OVERRIDE;
+
+  virtual AudioInputStream* MakeAudioInputStream(
+      const AudioParameters& params, const std::string& device_id) OVERRIDE;
 
   virtual AudioOutputStream* MakeAudioOutputStreamProxy(
       const AudioParameters& params) OVERRIDE;
 
   virtual bool IsRecordingInProcess() OVERRIDE;
 
+  // Called internally by the audio stream when it has been closed.
+  virtual void ReleaseOutputStream(AudioOutputStream* stream);
+  virtual void ReleaseInputStream(AudioInputStream* stream);
+
   void IncreaseActiveInputStreamCount();
   void DecreaseActiveInputStreamCount();
 
@@ -54,6 +64,28 @@ class MEDIA_EXPORT AudioManagerBase : public AudioManager {
   // Shutdown is called.
   void Shutdown();
 
+  // Returns the platform specific number of audio streams allowed. This is a
+  // practical limit to prevent failure caused by too many audio streams opened.
+  virtual int GetMaxOutputStreamsAllowed() = 0;

[tommi (sloooow) - chröme, 2012/03/06 16:16:04]

nit: Instead of a pure virtual function + implementation everywhere, we could
just have an int member variable in this class and an inline setter that can be
called in the constructor of the derived classes.

 protected:
  void set_max_output_streams(int max) { max_output_streams_ = max; }

 private:
  int max_output_streams_;  // initialized to something reasonable.


Then in derived classes:

MySpecialAudioManager() {
  set_max_output_streams(10);
}

[no longer working on chromium, 2012/03/06 17:38:41]

Done.

+
+  // Creates the output stream for the |AUDIO_PCM_LINEAR format|. The legacy
+  // name is also from |AUDIO_PCM_LINEAR|.
+  virtual AudioOutputStream* MakeLinearOutputStream(
+      const AudioParameters& params) = 0;
+
+  // Creates the output stream for the |AUDIO_PCM_LOW_LATENCY| format.
+  virtual AudioOutputStream* MakeLowLatencyOutputStream(
+      const AudioParameters& params) = 0;
+
+  // Creates the input stream for the |AUDIO_PCM_LINEAR format|. The legacy
+  // name is also from |AUDIO_PCM_LINEAR|.
+  virtual AudioInputStream* MakeLinearInputStream(
+      const AudioParameters& params, const std::string& device_id) = 0;
+
+  // Creates the input stream for the |AUDIO_PCM_LOW_LATENCY| format.
+  virtual AudioInputStream* MakeLowLatencyInputStream(
+      const AudioParameters& params, const std::string& device_id) = 0;
+
  protected:
   AudioManagerBase();
 
@@ -76,6 +108,9 @@ class MEDIA_EXPORT AudioManagerBase : public AudioManager {
   // is currently recording in Chrome.
   base::AtomicRefCount num_active_input_streams_;
 
+  // Number of currently open output streams.
+  int num_output_streams_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
 };