Integrate registry_hash_store_contents with the rest of tracked prefs.

components/user_prefs/tracked/dictionary_hash_store_contents.cc

 // Copyright (c) 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.
 
 #include "components/user_prefs/tracked/dictionary_hash_store_contents.h"
 
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/values.h"
@@ skipping 10 matching lines @@
     : storage_(storage) {
 }
 
 // static
 void DictionaryHashStoreContents::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   registry->RegisterDictionaryPref(kPreferenceMACs);
   registry->RegisterStringPref(kSuperMACPref, std::string());
 }
 
+std::unique_ptr<HashStoreContents> DictionaryHashStoreContents::MakeCopy()
+    const {
+  NOTREACHED() << "DictionaryHashStoreContents does not support MakeCopy";
+  return nullptr;
+}
+
+std::string DictionaryHashStoreContents::GetUMASuffix() const {
+  // To stay consistent with existing reported data, do not append a suffix
+  // when reporting UMA stats for this content.
+  return "";
+}
+
 void DictionaryHashStoreContents::Reset() {
   storage_->Remove(kPreferenceMACs, NULL);
 }
 
 bool DictionaryHashStoreContents::GetMac(const std::string& path,
                                          std::string* out_value) {
   const base::DictionaryValue* macs_dict = GetContents();
   if (macs_dict)
     return macs_dict->GetString(path, out_value);
 
@@ skipping 67 matching lines @@
 
 base::DictionaryValue* DictionaryHashStoreContents::GetMutableContents(
     bool create_if_null) {
   base::DictionaryValue* macs_dict = NULL;
   storage_->GetDictionary(kPreferenceMACs, &macs_dict);
   if (!macs_dict && create_if_null) {
     macs_dict = new base::DictionaryValue;
     storage_->Set(kPreferenceMACs, macs_dict);
   }
   return macs_dict;
-}
+}