Fix Chromium clang plugin warnings

webrtc/modules/audio_processing/vad/voice_activity_detector.cc

 /*
  *  Copyright (c) 2015 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 13 matching lines @@
 const double kNeutralProbability = 0.5;
 const double kLowProbability = 0.01;
 
 }  // namespace
 
 VoiceActivityDetector::VoiceActivityDetector()
     : last_voice_probability_(kDefaultVoiceValue),
       standalone_vad_(StandaloneVad::Create()) {
 }
 
+VoiceActivityDetector::~VoiceActivityDetector() = default;
+
 // Because ISAC has a different chunk length, it updates
 // |chunkwise_voice_probabilities_| and |chunkwise_rms_| when there is new data.
 // Otherwise it clears them.
 void VoiceActivityDetector::ProcessChunk(const int16_t* audio,
                                          size_t length,
                                          int sample_rate_hz) {
   RTC_DCHECK_EQ(static_cast<int>(length), sample_rate_hz / 100);
   RTC_DCHECK_LE(length, kMaxLength);
   // Resample to the required rate.
   const int16_t* resampled_ptr = audio;
@@ skipping 32 matching lines @@
           0);
       RTC_CHECK_GE(pitch_based_vad_.VoicingProbability(
                        features_, &chunkwise_voice_probabilities_[0]),
                    0);
     }
     last_voice_probability_ = chunkwise_voice_probabilities_.back();
   }
 }
 
 }  // namespace webrtc