Switching AudioInputDeviceManager from using AudioManager interface to AudioSystem one.

content/browser/browser_main_loop.h

Index: content/browser/browser_main_loop.h
diff --git a/content/browser/browser_main_loop.h b/content/browser/browser_main_loop.h
index 7755d8c1630b9eed826c1fa79631a69ae6da6753..d0af8e6cb041a591ce20bddb16c1cd3639fda058 100644
--- a/content/browser/browser_main_loop.h
+++ b/content/browser/browser_main_loop.h
@@ -15,6 +15,7 @@
 #include "content/browser/browser_process_sub_thread.h"
 #include "content/public/browser/browser_main_runner.h"
 #include "media/audio/audio_manager.h"
+#include "media/audio/audio_system.h"
 #include "services/resource_coordinator/memory/coordinator/coordinator_impl.h"
 
 #if defined(USE_AURA)
@@ -41,7 +42,6 @@ class DiscardableSharedMemoryManager;
 }
 
 namespace media {
-class AudioSystem;
 #if defined(OS_WIN)
 class SystemMessageWindowWin;
 #elif defined(OS_LINUX) && defined(USE_UDEV)
@@ -298,9 +298,7 @@ class CONTENT_EXPORT BrowserMainLoop {
   // AudioThread needs to outlive |audio_manager_|.
   std::unique_ptr<AudioManagerThread> audio_thread_;
   media::ScopedAudioManagerPtr audio_manager_;
-  // Calls to |audio_system_| must not be posted to the audio thread if it
-  // differs from the UI one.
-  std::unique_ptr<media::AudioSystem> audio_system_;
+  media::AudioSystem::UniquePtr audio_system_;
 
   std::unique_ptr<midi::MidiService> midi_service_;