Have ClientSocketPoolBase defriend base::RefCounted.

net/socket/client_socket_pool_base.h

 // Copyright (c) 2012 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.
 //
 // A ClientSocketPoolBase is used to restrict the number of sockets open at
 // a time.  It also maintains a list of idle persistent sockets for reuse.
 // Subclasses of ClientSocketPool should compose ClientSocketPoolBase to handle
 // the core logic of (1) restricting the number of active (connected or
 // connecting) sockets per "group" (generally speaking, the hostname), (2)
 // maintaining a per-group list of idle, persistent sockets for reuse, and (3)
@@ skipping 328 matching lines @@
 
   void EnableConnectBackupJobs();
 
   // ConnectJob::Delegate methods:
   void OnConnectJobComplete(int result, ConnectJob* job) override;
 
   // NetworkChangeNotifier::IPAddressObserver methods:
   void OnIPAddressChanged() override;
 
  private:
-  friend class base::RefCounted<ClientSocketPoolBaseHelper>;
-
   // Entry for a persistent socket which became idle at time |start_time|.
   struct IdleSocket {
     IdleSocket() : socket(NULL) {}
 
     // An idle socket can't be used if it is disconnected or has been used
     // before and has received data unexpectedly (hence no longer idle).  The
     // unread data would be mistaken for the beginning of the next response if
     // we were to use the socket for a new request.
     //
     // Note that a socket that has never been used before (like a preconnected
@@ skipping 513 matching lines @@
   };
 
   internal::ClientSocketPoolBaseHelper helper_;
 
   DISALLOW_COPY_AND_ASSIGN(ClientSocketPoolBase);
 };
 
 }  // namespace net
 
 #endif  // NET_SOCKET_CLIENT_SOCKET_POOL_BASE_H_