Fix Chromium clang plugin warnings

BUG=webrtc:163

Review-Url: https://codereview.webrtc.org/2288593004
Cr-Original-Commit-Position: refs/heads/master@{#13961}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 942c8515bc5f0936c1ebf894a426adf4d5392fc6
diff --git a/common_audio/blocker.cc b/common_audio/blocker.cc
index 13432f2..86dfdf3 100644
--- a/common_audio/blocker.cc
+++ b/common_audio/blocker.cc
@@ -125,6 +125,8 @@
   input_buffer_.MoveReadPositionBackward(initial_delay_);
 }
 
+Blocker::~Blocker() = default;
+
 // When block_size < chunk_size the input and output buffers look like this:
 //
 //                      delay*             chunk_size    chunk_size + delay*