Fix Chromium clang plugin warnings

BUG=webrtc:163

Review-Url: https://codereview.webrtc.org/2288593004
Cr-Commit-Position: refs/heads/master@{#13961}
diff --git a/webrtc/modules/audio_processing/test/test_utils.h b/webrtc/modules/audio_processing/test/test_utils.h
index 5de67cf..ca66520 100644
--- a/webrtc/modules/audio_processing/test/test_utils.h
+++ b/webrtc/modules/audio_processing/test/test_utils.h
@@ -47,6 +47,7 @@
 class ChannelBufferWavReader final {
  public:
   explicit ChannelBufferWavReader(std::unique_ptr<WavReader> file);
+  ~ChannelBufferWavReader();
 
   // Reads data from the file according to the |buffer| format. Returns false if
   // a full buffer can't be read from the file.
@@ -63,6 +64,8 @@
 class ChannelBufferWavWriter final {
  public:
   explicit ChannelBufferWavWriter(std::unique_ptr<WavWriter> file);
+  ~ChannelBufferWavWriter();
+
   void Write(const ChannelBuffer<float>& buffer);
 
  private: