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..9fbc5821ef5b4eef8128de44a1cdafe3f28ad78f 100644
--- a/media/audio/audio_manager_base.h
+++ b/media/audio/audio_manager_base.h
@@ -38,8 +38,14 @@ 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;
@@ -49,11 +55,31 @@ class MEDIA_EXPORT AudioManagerBase : public AudioManager {
   void IncreaseActiveInputStreamCount();
   void DecreaseActiveInputStreamCount();
 
+  // Called internally by the audio stream when it has been closed.
+  virtual void ReleaseOutputStream(AudioOutputStream* stream);
+  virtual void ReleaseInputStream(AudioInputStream* stream);
+
   // Shuts down the audio thread and releases all the audio output dispatchers
   // on the audio thread.  All AudioOutputProxy instances should be freed before
   // 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 GetMaxAudioOutputStreamsAllowed() = 0;
+
+  virtual AudioOutputStream* MakeAudioLinearOutputStream(
+      const AudioParameters& params) = 0;
+
+  virtual AudioOutputStream* MakeAudioLowLatencyOutputStream(
+      const AudioParameters& params) = 0;
+
+  virtual AudioInputStream* MakeAudioLinearInputStream(
+      const AudioParameters& params, const std::string& device_id) = 0;
+
+  virtual AudioInputStream* MakeAudioLowLatencyInputStream(
+      const AudioParameters& params, const std::string& device_id) = 0;
+
  protected:
   AudioManagerBase();
 
@@ -76,6 +102,9 @@ 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);
 };