Fix Chromium clang plugin warnings

NOTRY=true
BUG=webrtc:163

Review-Url: https://codereview.webrtc.org/2286063005
Cr-Commit-Position: refs/heads/master@{#13955}

webrtc/modules/audio_coding/acm2/audio_coding_module.cc

@@ -1268,6 +1268,16 @@ void AudioCodingModuleImpl::GetDecodingCallStatistics(
 
 }  // namespace
 
+AudioCodingModule::Config::Config()
+    : id(0), neteq_config(), clock(Clock::GetRealTimeClock()) {
+  // Post-decode VAD is disabled by default in NetEq, however, Audio
+  // Conference Mixer relies on VAD decisions and fails without them.
+  neteq_config.enable_post_decode_vad = true;
+}
+
+AudioCodingModule::Config::Config(const Config&) = default;
+AudioCodingModule::Config::~Config() = default;
+
 // Create module
 AudioCodingModule* AudioCodingModule::Create(int id) {
   Config config;