Add tracing to NetEqImpl::GetAudio

BUG=webrtc:5167
R=pbos@webrtc.org
NOTRY=true

Review URL: https://codereview.webrtc.org/1571693002

Cr-Commit-Position: refs/heads/master@{#11183}

webrtc/modules/audio_coding/neteq/neteq_impl.cc

@@ -153,6 +153,7 @@ int NetEqImpl::InsertSyncPacket(const WebRtcRTPHeader& rtp_header,
 int NetEqImpl::GetAudio(size_t max_length, int16_t* output_audio,
                         size_t* samples_per_channel, int* num_channels,
                         NetEqOutputType* type) {
+  TRACE_EVENT0("webrtc", "NetEqImpl::GetAudio");
   CriticalSectionScoped lock(crit_sect_.get());
   int error = GetAudioInternal(max_length, output_audio, samples_per_channel,
                                num_channels);