[cros] RlzValueStore made protected by a cross-process lock and not persisted over browser lifetime…

base/files/important_file_writer.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 BASE_FILES_IMPORTANT_FILE_WRITER_H_
 #define BASE_FILES_IMPORTANT_FILE_WRITER_H_
 
 #include <string>
 
 #include "base/base_export.h"
@@ skipping 33 matching lines @@
    public:
     // Should put serialized string in |data| and return true on successful
     // serialization. Will be called on the same thread on which
     // ImportantFileWriter has been created.
     virtual bool SerializeData(std::string* data) = 0;
 
    protected:
     virtual ~DataSerializer() {}
   };
 
+  // Save |data| to |path| in an atomic manner (see the class comment above).
+  // Blocks and writes data on the current thread.
+  static bool WriteFileAtomically(const FilePath& path,
+                                  const std::string& data);
+
   // Initialize the writer.
   // |path| is the name of file to write.
   // |task_runner| is the SequencedTaskRunner instance where on which we will
   // execute file I/O operations.
   // All non-const methods, ctor and dtor must be called on the same thread.
   ImportantFileWriter(const FilePath& path,
                       base::SequencedTaskRunner* task_runner);
 
   // You have to ensure that there are no pending writes at the moment
   // of destruction.
@@ skipping 43 matching lines @@
 
   // Time delta after which scheduled data will be written to disk.
   TimeDelta commit_interval_;
 
   DISALLOW_COPY_AND_ASSIGN(ImportantFileWriter);
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_IMPORTANT_FILE_WRITER_H_