Use make_ref_counted in AudioProcessingBuilder

Bug: webrtc:12701
Change-Id: I51ca5a54f812a1620ee2e6605c9ff67b92e2a5f8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/224547
Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34725}
diff --git a/modules/audio_processing/include/audio_processing.h b/modules/audio_processing/include/audio_processing.h
index 6761ed4..02a961a 100644
--- a/modules/audio_processing/include/audio_processing.h
+++ b/modules/audio_processing/include/audio_processing.h
@@ -815,8 +815,8 @@
   }
   // This creates an APM instance using the previously set components. Calling
   // the Create function resets the AudioProcessingBuilder to its initial state.
-  AudioProcessing* Create();
-  AudioProcessing* Create(const webrtc::Config& config);
+  rtc::scoped_refptr<AudioProcessing> Create();
+  rtc::scoped_refptr<AudioProcessing> Create(const webrtc::Config& config);
 
  private:
   std::unique_ptr<EchoControlFactory> echo_control_factory_;