net doesn't depend on libevent directly now.

net/udp/udp_socket_libevent.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/udp/udp_socket_libevent.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <netdb.h>
 #include <sys/socket.h>
 
 #include "base/eintr_wrapper.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/metrics/stats_counters.h"
 #include "net/base/io_buffer.h"
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
 #include "net/base/net_util.h"
 #if defined(OS_POSIX)
 #include <netinet/in.h>
 #endif
-#if defined(USE_SYSTEM_LIBEVENT)
-#include <event.h>
-#else
-#include "third_party/libevent/event.h"
-#endif
 
 namespace net {
 
 UDPSocketLibevent::UDPSocketLibevent(net::NetLog* net_log,
                                      const net::NetLog::Source& source)
     : socket_(kInvalidSocket),
       read_watcher_(this),
       write_watcher_(this),
       read_buf_len_(0),
       recv_from_address_(NULL),
@@ skipping 319 matching lines @@
 
   return HANDLE_EINTR(sendto(socket_,
                              buf->data(),
                              buf_len,
                              0,
                              addr,
                              addr_len));
 }
 
 }  // namespace net