Fix Chromium clang plugin warnings

webrtc/common_audio/sparse_fir_filter.h

Index: webrtc/common_audio/sparse_fir_filter.h
diff --git a/webrtc/common_audio/sparse_fir_filter.h b/webrtc/common_audio/sparse_fir_filter.h
index 2ba5cf4600d7b2d0c64b75a9af0cc5d886556ae2..2d406a0f19e03c60e94855a119ba2daf5ed4a204 100644
--- a/webrtc/common_audio/sparse_fir_filter.h
+++ b/webrtc/common_audio/sparse_fir_filter.h
@@ -33,6 +33,7 @@ class SparseFIRFilter final {
                   size_t num_nonzero_coeffs,
                   size_t sparsity,
                   size_t offset);
+  ~SparseFIRFilter();
 
   // Filters the |in| data supplied.
   // |out| must be previously allocated and it must be at least of |length|.