Switching AudioInputDeviceManager from using AudioManager interface to AudioSystem one.

media/audio/audio_system.h

Index: media/audio/audio_system.h
diff --git a/media/audio/audio_system.h b/media/audio/audio_system.h
index 66dc622db267575d189e74adc5fb4729c6fbc6c7..857a343d75a066d38d6a820f49b37bea0b881305 100644
--- a/media/audio/audio_system.h
+++ b/media/audio/audio_system.h
@@ -23,13 +23,18 @@ class AudioManager;
 class MEDIA_EXPORT AudioSystem {
  public:
   // Replies are asynchronously sent from audio system thread to the thread the
-  // call is issued on. Attention! Since audio system thread may outlive all the
-  // others, callbacks must always be bound to weak pointers!
+  // call is issued on. Attention! Audio system thread may outlive the client
+  // objects; bind callbacks with care.
   using OnAudioParamsCallback = base::Callback<void(const AudioParameters&)>;
   using OnBoolCallback = base::Callback<void(bool)>;
   using OnDeviceDescriptionsCallback =
       base::Callback<void(AudioDeviceDescriptions)>;
+  using OnDeviceIdCallback = base::Callback<void(const std::string&)>;
+  using OnInputDeviceInfoCallback = base::Callback<
+      void(const AudioParameters&, const AudioParameters&, const std::string&)>;
 
+  // Must not be called on audio system thread if it differs from the one

[DaleCurtis, 2017/04/06 18:37:17]

I'd prefer not to land this without resolving this first unless you expect this
warning to have no effect  on any current or near term callers (~few weeks).
Otherwise we end up in a situation where AM destruction complexity is leaking
into new areas.

[o1ka, 2017/04/07 12:22:17]

It's just a comment describing the current situation which have existed before
the CL. I also added a link to the bug. No new callers are expected. It's a
problem similar to AudioManager::Get(), which still exists and which we had
number of bugs for. The issue should be covered with AM and AS lifetime / audio
thread stop fix.

The only effect would be on this CL if we decide to use 3 separate AudioSystem
calls instead of all-in-one AudioSystem::GetInputDeviceInfo(). If we choose to
do so, we need to post AudioSystem operations on the audio thread and the CL
cannot be landed until lifetime issues are fixed.

But it does not affect the CL as it is now (with GetInputDeviceInfo()).

+  // AudioSystem is destroyed on.
   static AudioSystem* Get();
 
   virtual ~AudioSystem();
@@ -59,13 +64,22 @@ class MEDIA_EXPORT AudioSystem {
   // Replies with device descriptions of input audio devices if |for_input| is
   // true, and of output audio devices otherwise.
   virtual void GetDeviceDescriptions(
-      OnDeviceDescriptionsCallback on_descriptions_cp,
+      OnDeviceDescriptionsCallback on_descriptions_cb,
       bool for_input) = 0;
 
-  virtual base::SingleThreadTaskRunner* GetTaskRunner() const = 0;
+  // Replies with an empty string if there is no associated output device found.
+  virtual void GetAssociatedOutputDeviceID(
+      const std::string& input_device_id,
+      OnDeviceIdCallback on_device_id_cb) = 0;
+
+  // Replies with audio parameters for the specified input device and audio
+  // parameters and device ID of the associated output device, if any (otherwise
+  // it's AudioParameters() and an empty string).
+  virtual void GetInputDeviceInfo(
+      const std::string& input_device_id,
+      OnInputDeviceInfoCallback on_input_device_info_cb) = 0;
 
-  // Must not be used for anything but stream creation.
-  virtual AudioManager* GetAudioManager() const = 0;
+  virtual base::SingleThreadTaskRunner* GetTaskRunner() const = 0;
 
  protected:
   // Sets the global AudioSystem pointer to the specified non-null value.