Split the NullInitialized signal out of TrustedInitialized.

chrome/browser/prefs/tracked/pref_hash_store_transaction.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_PREF_HASH_STORE_TRANSACTION_H_
 #define CHROME_BROWSER_PREFS_TRACKED_PREF_HASH_STORE_TRANSACTION_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 14 matching lines @@
     // calculated using a deprecated hash algorithm which is just as safe as
     // the current one.
     SECURE_LEGACY,
     // The preference value has been changed since the last hash.
     CHANGED,
     // No stored hash exists for the preference value.
     UNTRUSTED_UNKNOWN_VALUE,
     // No stored hash exists for the preference value, but the current set of
     // hashes stored is trusted and thus this value can safely be seeded. This
     // happens when all hashes are already properly seeded and a newly
-    // tracked value needs to be seeded). NULL values are inherently trusted as
-    // well.
+    // tracked value needs to be seeded).
     TRUSTED_UNKNOWN_VALUE,
+    // NULL values are inherently trusted.
+    TRUSTED_NULL_VALUE,
   };
 
   // Finalizes any remaining work after the transaction has been performed.
   virtual ~PrefHashStoreTransaction() {}
 
   // Checks |initial_value| against the existing stored value hash.
   virtual ValueState CheckValue(
       const std::string& path, const base::Value* initial_value) const = 0;
 
   // Stores a hash of the current |value| of the preference at |path|.
@@ skipping 38 matching lines @@
   // Indicates whether the super MAC was successfully verified at the beginning
   // of this transaction.
   virtual bool IsSuperMACValid() const = 0;
 
   // Forces a valid super MAC to be stored when this transaction terminates.
   // Returns true if this results in a change to the store contents.
   virtual bool StampSuperMac() = 0;
 };
 
 #endif  // CHROME_BROWSER_PREFS_TRACKED_PREF_HASH_STORE_TRANSACTION_H_