Fix net_export.h includes.

net/quic/core/quic_sent_entropy_manager.h

 // Copyright 2013 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.
 //
 // Manages the packet entropy calculation for both sent and received packets
 // for a connection.
 
 #ifndef NET_QUIC_QUIC_SENT_ENTROPY_MANAGER_H_
 #define NET_QUIC_QUIC_SENT_ENTROPY_MANAGER_H_
 
 #include <deque>
 
 #include "base/macros.h"
 #include "net/base/linked_hash_map.h"
+#include "net/base/net_export.h"
 #include "net/quic/core/quic_framer.h"
 #include "net/quic/core/quic_protocol.h"
 
 namespace net {
 
 namespace test {
 class QuicConnectionPeer;
 }  // namespace test
 
 // Records all sent packets by a connection to track the cumulative entropy of
@@ skipping 54 matching lines @@
 
   // Cache the cumulative entropy for the packet number used by EntropyHash.
   CumulativeEntropy last_cumulative_entropy_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicSentEntropyManager);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_SENT_ENTROPY_MANAGER_H_