Add TRACE_EVENT macros to net.

net/socket/transport_client_socket_pool.cc

Index: net/socket/transport_client_socket_pool.cc
diff --git a/net/socket/transport_client_socket_pool.cc b/net/socket/transport_client_socket_pool.cc
index 94f97c26c8a86f4510ad0ad8d758da5ee8b8f270..dbc701a938681a2d074f217b1025ce247d57ee4a 100644
--- a/net/socket/transport_client_socket_pool.cc
+++ b/net/socket/transport_client_socket_pool.cc
@@ -16,6 +16,7 @@
 #include "base/strings/string_util.h"
 #include "base/synchronization/lock.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "base/values.h"
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_errors.h"
@@ -115,6 +116,7 @@ int TransportConnectJobHelper::DoResolveHost(RequestPriority priority,
 int TransportConnectJobHelper::DoResolveHostComplete(
     int result,
     const BoundNetLog& net_log) {
+  TRACE_EVENT0("net", "TransportConnectJobHelper::DoResolveHostComplete");
   connect_timing_->dns_end = base::TimeTicks::Now();
   // Overwrite connection start time, since for connections that do not go
   // through proxies, |connect_start| should not include dns lookup time.