Delete unused BluetoothAudioSink code.

device/bluetooth/bluetooth_adapter_win.h

Index: device/bluetooth/bluetooth_adapter_win.h
diff --git a/device/bluetooth/bluetooth_adapter_win.h b/device/bluetooth/bluetooth_adapter_win.h
index fbbcb7f644c834c32e31fb3c57cc64cc4196cd92..cdaeead7621440dc69443c961206c9e890125af2 100644
--- a/device/bluetooth/bluetooth_adapter_win.h
+++ b/device/bluetooth/bluetooth_adapter_win.h
@@ -20,7 +20,6 @@
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "device/bluetooth/bluetooth_adapter.h"
-#include "device/bluetooth/bluetooth_audio_sink.h"
 #include "device/bluetooth/bluetooth_discovery_session.h"
 #include "device/bluetooth/bluetooth_export.h"
 #include "device/bluetooth/bluetooth_task_manager_win.h"
@@ -71,10 +70,6 @@ class DEVICE_BLUETOOTH_EXPORT BluetoothAdapterWin
       const ServiceOptions& options,
       const CreateServiceCallback& callback,
       const CreateServiceErrorCallback& error_callback) override;
-  void RegisterAudioSink(
-      const BluetoothAudioSink::Options& options,
-      const AcquiredCallback& callback,
-      const BluetoothAudioSink::ErrorCallback& error_callback) override;
   void RegisterAdvertisement(
       std::unique_ptr<BluetoothAdvertisement::Data> advertisement_data,
       const CreateAdvertisementCallback& callback,