DNS: Add stubs for persisting data across restarts

net/dns/dns_session.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.
 
 #ifndef NET_DNS_DNS_SESSION_H_
 #define NET_DNS_DNS_SESSION_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 92 matching lines @@
   // Allocate a socket, already connected to the server address.
   // When the SocketLease is destroyed, the socket will be freed.
   std::unique_ptr<SocketLease> AllocateSocket(unsigned server_index,
                                               const NetLog::Source& source);
 
   // Creates a StreamSocket from the factory for a transaction over TCP. These
   // sockets are not pooled.
   std::unique_ptr<StreamSocket> CreateTCPSocket(unsigned server_index,
                                                 const NetLog::Source& source);
 
+  void ApplyPersistentData(const base::Value& data);
+  std::unique_ptr<const base::Value> GetPersistentData() const;
+
  private:
   friend class base::RefCounted<DnsSession>;
   ~DnsSession() override;
 
   void UpdateTimeouts(NetworkChangeNotifier::ConnectionType type);
   void InitializeServerStats();
 
   // Release a socket.
   void FreeSocket(unsigned server_index,
                   std::unique_ptr<DatagramClientSocket> socket);
@@ skipping 29 matching lines @@
     RttBuckets();
   };
   static base::LazyInstance<RttBuckets>::Leaky rtt_buckets_;
 
   DISALLOW_COPY_AND_ASSIGN(DnsSession);
 };
 
 }  // namespace net
 
 #endif  // NET_DNS_DNS_SESSION_H_