Fix Chromium clang plugin warnings

webrtc/modules/audio_processing/agc/agc.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 22 matching lines @@
   // left) channel.
   virtual int Process(const int16_t* audio, size_t length, int sample_rate_hz);
 
   // Retrieves the difference between the target RMS level and the current
   // signal RMS level in dB. Returns true if an update is available and false
   // otherwise, in which case |error| should be ignored and no action taken.
   virtual bool GetRmsErrorDb(int* error);
   virtual void Reset();
 
   virtual int set_target_level_dbfs(int level);
-  virtual int target_level_dbfs() const { return target_level_dbfs_; }
-
-  virtual float voice_probability() const {
-    return vad_.last_voice_probability();
-  }
+  virtual int target_level_dbfs() const;
+  virtual float voice_probability() const;
 
  private:
   double target_level_loudness_;
   int target_level_dbfs_;
   std::unique_ptr<LoudnessHistogram> histogram_;
   std::unique_ptr<LoudnessHistogram> inactive_histogram_;
   VoiceActivityDetector vad_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AGC_AGC_H_