Fix the hash generation algorithm to be consistent with prior implementation.

chrome/browser/prefs/pref_hash_calculator.h

Index: chrome/browser/prefs/pref_hash_calculator.h
diff --git a/chrome/browser/prefs/pref_hash_calculator.h b/chrome/browser/prefs/pref_hash_calculator.h
index 6f0fd851790c341d8baae1241f4f27d427fa3513..9e287750e4f7462445e0d3e0b64af41920af7704 100644
--- a/chrome/browser/prefs/pref_hash_calculator.h
+++ b/chrome/browser/prefs/pref_hash_calculator.h
@@ -39,11 +39,6 @@ class PrefHashCalculator {
                             const std::string& hash) const;
 
  private:
-  // Calculate a hash using a deprecated hash algorithm. For validating old
-  // hashes during migration.
-  std::string CalculateLegacyHash(const std::string& path,
-                                  const base::Value* value) const;
-
   std::string seed_;
   std::string device_id_;