[NOT FOR REVIEW] Instrument net/ with trace events.

net/url_request/url_request_http_job.cc

Index: net/url_request/url_request_http_job.cc
diff --git a/net/url_request/url_request_http_job.cc b/net/url_request/url_request_http_job.cc
index ccc38d544ead9009417fdda7e4b7595c53defc7e..b444d539be701f4b3a77e131f535a108d4c25293 100644
--- a/net/url_request/url_request_http_job.cc
+++ b/net/url_request/url_request_http_job.cc
@@ -55,6 +55,8 @@
 #include "net/websockets/websocket_handshake_stream_base.h"
 #include "url/origin.h"
 
+#include "base/trace_event/trace_event.h"
+
 static const char kAvailDictionaryHeader[] = "Avail-Dictionary";
 
 namespace {
@@ -1034,6 +1036,7 @@ void URLRequestHttpJob::OnHeadersReceivedCallback(int result) {
 }
 
 void URLRequestHttpJob::OnReadCompleted(int result) {
+  TRACE_EVENT0("net", "net::URLRequestHttpJob::OnReadCompleted");
   read_in_progress_ = false;
 
   DCHECK_NE(ERR_IO_PENDING, result);