Cleanup: Another round of unused forward declaration cleanup.

net/http/http_network_session_peer.h

 // 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.
 
 #ifndef NET_HTTP_HTTP_NETWORK_SESSION_PEER_H_
 #define NET_HTTP_HTTP_NETWORK_SESSION_PEER_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "net/base/net_export.h"
 
 namespace net {
 
 class ClientSocketPoolManager;
-class HostPortPair;
 class HttpNetworkSession;
 class HttpStreamFactory;
 class ProxyService;
 
 class NET_EXPORT_PRIVATE HttpNetworkSessionPeer {
  public:
   explicit HttpNetworkSessionPeer(
       const scoped_refptr<HttpNetworkSession>& session);
   ~HttpNetworkSessionPeer();
 
   void SetClientSocketPoolManager(
       ClientSocketPoolManager* socket_pool_manager);
 
   void SetProxyService(ProxyService* proxy_service);
 
   void SetHttpStreamFactory(HttpStreamFactory* http_stream_factory);
 
  private:
   const scoped_refptr<HttpNetworkSession> session_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpNetworkSessionPeer);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_NETWORK_SESSION_PEER_H_