Make GetConfig() part of the AudioProcessing interface

webrtc/modules/audio_processing/audio_processing_impl.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 116 matching lines @@
   // during APM creation).
   EchoCancellation* echo_cancellation() const override;
   EchoControlMobile* echo_control_mobile() const override;
   GainControl* gain_control() const override;
   // TODO(peah): Deprecate this API call.
   HighPassFilter* high_pass_filter() const override;
   LevelEstimator* level_estimator() const override;
   NoiseSuppression* noise_suppression() const override;
   VoiceDetection* voice_detection() const override;
 
-  // TODO(peah): Remove these two methods once the new API allows that.
+  // TODO(peah): Remove MutateConfig once the new API allows that.
   void MutateConfig(rtc::FunctionView<void(AudioProcessing::Config*)> mutator);
-  AudioProcessing::Config GetConfig() const;
+  AudioProcessing::Config GetConfig() const override;
 
  protected:
   // Overridden in a mock.
   virtual int InitializeLocked()
       EXCLUSIVE_LOCKS_REQUIRED(crit_render_, crit_capture_);
 
  private:
   // TODO(peah): These friend classes should be removed as soon as the new
   // parameter setting scheme allows.
   FRIEND_TEST_ALL_PREFIXES(ApmConfiguration, DefaultBehavior);
@@ skipping 278 matching lines @@
   std::unique_ptr<
       SwapQueue<std::vector<int16_t>, RenderQueueItemVerifier<int16_t>>>
       agc_render_signal_queue_;
   std::unique_ptr<SwapQueue<std::vector<float>, RenderQueueItemVerifier<float>>>
       red_render_signal_queue_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AUDIO_PROCESSING_IMPL_H_