Add TRACE_EVENT macros to net.

net/socket/socket_posix.cc

Index: net/socket/socket_posix.cc
diff --git a/net/socket/socket_posix.cc b/net/socket/socket_posix.cc
index 96892891d097eda59ee1c4ac5b65266532ebf636..ca8b04f09a4741282f7d441711d87ba315332ce3 100644
--- a/net/socket/socket_posix.cc
+++ b/net/socket/socket_posix.cc
@@ -13,6 +13,7 @@
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/posix/eintr_wrapper.h"
+#include "base/trace_event/trace_event.h"
 #include "net/base/io_buffer.h"
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_errors.h"
@@ -348,6 +349,7 @@ void SocketPosix::DetachFromThread() {
 }
 
 void SocketPosix::OnFileCanReadWithoutBlocking(int fd) {
+  TRACE_EVENT0("net", "SocketPosix::OnFileCanReadWithoutBlocking");
   DCHECK(!accept_callback_.is_null() || !read_callback_.is_null());
   if (!accept_callback_.is_null()) {
     AcceptCompleted();