Move ImportantFileWriter to base/. It now has two consumers, base/prefs and chrome/.

chrome/browser/net/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 18 matching lines @@
 // TransportSecurityPersister::SerializeState
 //   copies the current state of the TransportSecurityState, serializes
 //   and writes to disk.
 
 #ifndef CHROME_BROWSER_NET_TRANSPORT_SECURITY_PERSISTER_H_
 #define CHROME_BROWSER_NET_TRANSPORT_SECURITY_PERSISTER_H_
 
 #include <string>
 
 #include "base/file_path.h"
+#include "base/files/important_file_writer.h"
 #include "base/memory/weak_ptr.h"
-#include "chrome/common/important_file_writer.h"
 #include "net/base/transport_security_state.h"
 
 // Reads and updates on-disk TransportSecurity state.
 // Must be created, used and destroyed only on the IO thread.
 class TransportSecurityPersister
     : public net::TransportSecurityState::Delegate,
-      public ImportantFileWriter::DataSerializer {
+      public base::ImportantFileWriter::DataSerializer {
  public:
   TransportSecurityPersister(net::TransportSecurityState* state,
                              const FilePath& profile_path,
                              bool readonly);
   virtual ~TransportSecurityPersister();
 
   // Called by the TransportSecurityState when it changes its state.
   virtual void StateIsDirty(net::TransportSecurityState*) OVERRIDE;
 
   // ImportantFileWriter::DataSerializer:
@@ skipping 52 matching lines @@
   static bool Deserialize(const std::string& serialized,
                           bool forced,
                           bool* dirty,
                           net::TransportSecurityState* state);
 
   void CompleteLoad(const std::string& state);
 
   net::TransportSecurityState* transport_security_state_;
 
   // Helper for safely writing the data.
-  ImportantFileWriter writer_;
+  base::ImportantFileWriter writer_;
 
   // Whether or not we're in read-only mode.
   const bool readonly_;
 
   base::WeakPtrFactory<TransportSecurityPersister> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TransportSecurityPersister);
 };
 
 #endif  // CHROME_BROWSER_NET_TRANSPORT_SECURITY_PERSISTER_H_