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..a55bf8c44255aed8327afabbac9e1306e640847f 100644
--- a/media/audio/audio_system.h
+++ b/media/audio/audio_system.h
@@ -6,6 +6,7 @@
 #define MEDIA_AUDIO_AUDIO_SYSTEM_H_
 
 #include "base/callback.h"
+#include "base/memory/weak_ptr.h"
 #include "media/audio/audio_device_description.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/media_export.h"
@@ -22,6 +23,13 @@ class AudioManager;
 // to Mojo audio service.
 class MEDIA_EXPORT AudioSystem {
  public:
+  class OnAudioThreadDeleter {
+   public:
+    void operator()(const AudioSystem* instance) const;
+  };
+
+  using UniquePtr = std::unique_ptr<AudioSystem, OnAudioThreadDeleter>;
+
   // 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!
@@ -29,7 +37,9 @@ class MEDIA_EXPORT AudioSystem {
   using OnBoolCallback = base::Callback<void(bool)>;
   using OnDeviceDescriptionsCallback =
       base::Callback<void(AudioDeviceDescriptions)>;
+  using OnDeviceIdCallback = base::Callback<void(const std::string&)>;
 
+  // Must not be called on audio thread, since it outlives the global pointer.
   static AudioSystem* Get();
 
   virtual ~AudioSystem();
@@ -59,9 +69,18 @@ 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 void GetAssociatedOutputDeviceID(
+      const std::string& input_device_id,
+      OnDeviceIdCallback on_device_id_cb) = 0;
+
+  // To be used on audio thread only.

[DaleCurtis, 2017/03/22 19:08:34]

Sorry, this is bad practice, can you find another way to achieve what you're
trying to do here? We  try to avoid vending WeakPtrs to outside classes. Instead
lifetime needs to be managed such that this class outlives everything that
should all it.

+  // AudioSystem instance must be posted to its task runner in form of a weak
+  // pointer, since the task runner outlives it.
+  virtual base::WeakPtr<AudioSystem> GetWeakPtr() = 0;
+
   virtual base::SingleThreadTaskRunner* GetTaskRunner() const = 0;
 
   // Must not be used for anything but stream creation.