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chrome/browser/prefs/tracked/hash_store_contents.h

 // Copyright 2014 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 CHROME_BROWSER_PREFS_TRACKED_HASH_STORE_CONTENTS_H_
 #define CHROME_BROWSER_PREFS_TRACKED_HASH_STORE_CONTENTS_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 
 namespace base {
 class DictionaryValue;
 } // namespace base
 
-// Provides access to the contents of a preference hash store.
+// Provides access to the contents of a preference hash store. The store
+// contains the following data:
+// Contents: a client-defined dictionary that should map preference names to
+// MACs.
+// Version: a client-defined version number for the format of Contents.
+// Super MAC: a MAC that authenticates the entirety of Contents.
+// Legacy hash stores may have an ID that was incorporated into MAC
+// calculations. The ID, if any, is available via |hash_store_id()|.
 class HashStoreContents {
  public:
   // Used to modify a DictionaryValue stored in the preference hash store. The
   // MutableDictionary should be destroyed when modifications are complete in
   // order to allow them to be committed to the underlying storage.
   class MutableDictionary {
    public:
     virtual ~MutableDictionary() {}
     // Returns the DictionaryValue, which will be created if it does not already
     // exist.
@@ skipping 27 matching lines @@
 
   // Retrieves the super MAC value previously stored by SetSuperMac. May be
   // empty if no super MAC has been stored.
   virtual std::string GetSuperMac() const = 0;
 
   // Stores a super MAC value for this hash store.
   virtual void SetSuperMac(const std::string& super_mac) = 0;
 };
 
 #endif  // CHROME_BROWSER_PREFS_TRACKED_HASH_STORE_CONTENTS_H_