Revert of Integrate registry_hash_store_contents with the rest of tracked prefs.

components/user_prefs/tracked/tracked_atomic_preference.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 COMPONENTS_USER_PREFS_TRACKED_ATOMIC_PREFERENCE_H_
 #define COMPONENTS_USER_PREFS_TRACKED_ATOMIC_PREFERENCE_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 12 matching lines @@
 class TrackedAtomicPreference : public TrackedPreference {
  public:
   TrackedAtomicPreference(const std::string& pref_path,
                           size_t reporting_id,
                           size_t reporting_ids_count,
                           PrefHashFilter::EnforcementLevel enforcement_level,
                           PrefHashFilter::ValueType value_type,
                           TrackedPreferenceValidationDelegate* delegate);
 
   // TrackedPreference implementation.
-  TrackedPreferenceType GetType() const override;
   void OnNewValue(const base::Value* value,
                   PrefHashStoreTransaction* transaction) const override;
-  bool EnforceAndReport(
-      base::DictionaryValue* pref_store_contents,
-      PrefHashStoreTransaction* transaction,
-      PrefHashStoreTransaction* external_validation_transaction) const override;
+  bool EnforceAndReport(base::DictionaryValue* pref_store_contents,
+                        PrefHashStoreTransaction* transaction) const override;
 
  private:
   const std::string pref_path_;
   const TrackedPreferenceHelper helper_;
   TrackedPreferenceValidationDelegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(TrackedAtomicPreference);
 };
 
 #endif  // COMPONENTS_USER_PREFS_TRACKED_ATOMIC_PREFERENCE_H_