Implement standalone event tracing in AppRTCDemo.

webrtc/call/call.cc

Index: webrtc/call/call.cc
diff --git a/webrtc/call/call.cc b/webrtc/call/call.cc
index 326c1bad3e25c9538ab497eb3358b4c807cdde06..dfec9d58a2eb42e331f63b723f4730abdeaa4212 100644
--- a/webrtc/call/call.cc
+++ b/webrtc/call/call.cc
@@ -668,6 +668,7 @@ void Call::ConfigureSync(const std::string& sync_group) {
 PacketReceiver::DeliveryStatus Call::DeliverRtcp(MediaType media_type,
                                                  const uint8_t* packet,
                                                  size_t length) {
+  TRACE_EVENT0("webrtc", "Call::DeliverRtcp");
   // TODO(pbos): Figure out what channel needs it actually.
   //             Do NOT broadcast! Also make sure it's a valid packet.
   //             Return DELIVERY_UNKNOWN_SSRC if it can be determined that
@@ -701,6 +702,7 @@ PacketReceiver::DeliveryStatus Call::DeliverRtp(MediaType media_type,
                                                 const uint8_t* packet,
                                                 size_t length,
                                                 const PacketTime& packet_time) {
+  TRACE_EVENT0("webrtc", "Call::DeliverRtp");
   // Minimum RTP header size.
   if (length < 12)
     return DELIVERY_PACKET_ERROR;