Add TRACE_EVENT macros to net.

net/spdy/spdy_session.cc

Index: net/spdy/spdy_session.cc
diff --git a/net/spdy/spdy_session.cc b/net/spdy/spdy_session.cc
index 3ab0112f4c6ad5dc7d69ed55e7483682f79b845b..5a9a90d7533f3600b17e5d90b8a2caed043e43ee 100644
--- a/net/spdy/spdy_session.cc
+++ b/net/spdy/spdy_session.cc
@@ -24,6 +24,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "base/values.h"
 #include "crypto/ec_private_key.h"
 #include "crypto/ec_signature_creator.h"
@@ -1387,6 +1388,7 @@ void SpdySession::EnqueueResetStreamFrame(SpdyStreamId stream_id,
 }
 
 void SpdySession::PumpReadLoop(ReadState expected_read_state, int result) {
+  TRACE_EVENT0("net", "SpdySession::PumpReadLoop");
   // TODO(bnc): Remove ScopedTracker below once crbug.com/462774 is fixed.
   tracked_objects::ScopedTracker tracking_profile(
       FROM_HERE_WITH_EXPLICIT_FUNCTION("462774 SpdySession::PumpReadLoop"));