Implement lossy pref behavior for JsonPrefStore.

net/http/transport_security_persister.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.
 
 // TransportSecurityState maintains an in memory database containing the
 // list of hosts that currently have transport security enabled. This
 // singleton object deals with writing that data out to disk as needed and
 // loading it at startup.
 
 // At startup we need to load the transport security state from the
@@ skipping 103 matching lines @@
   // state; false otherwise.
   static bool Deserialize(const std::string& serialized,
                           bool* dirty,
                           TransportSecurityState* state);
 
   void CompleteLoad(const std::string& state);
 
   TransportSecurityState* transport_security_state_;
 
   // Helper for safely writing the data.
-  base::ImportantFileWriter writer_;
+  scoped_ptr<base::ImportantFileWriterImpl> writer_;
 
   scoped_refptr<base::SequencedTaskRunner> foreground_runner_;
   scoped_refptr<base::SequencedTaskRunner> background_runner_;
 
   // Whether or not we're in read-only mode.
   const bool readonly_;
 
   base::WeakPtrFactory<TransportSecurityPersister> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TransportSecurityPersister);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_TRANSPORT_SECURITY_PERSISTER_H_