Use std::unique_ptr for base::DictionaryValue and base::ListValue's internal store.

components/ntp_snippets/ntp_snippets_service.cc

 // Copyright 2015 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/ntp_snippets/ntp_snippets_service.h"
 
 #include <algorithm>
 #include <iterator>
 #include <utility>
 
@@ skipping 485 matching lines @@
 }
 
 void NTPSnippetsService::StoreDiscardedSnippetsToPrefs() {
   pref_service_->Set(prefs::kDiscardedSnippets,
                      *SnippetsToListValue(discarded_snippets_));
 }
 
 std::set<std::string> NTPSnippetsService::GetSnippetHostsFromPrefs() const {
   std::set<std::string> hosts;
   const base::ListValue* list = pref_service_->GetList(prefs::kSnippetHosts);
-  for (const base::Value* value : *list) {
+  for (const auto& value : *list) {
     std::string str;
     bool success = value->GetAsString(&str);
     DCHECK(success) << "Failed to parse snippet host from prefs";
     hosts.insert(std::move(str));
   }
   return hosts;
 }
 
 void NTPSnippetsService::StoreSnippetHostsToPrefs(
     const std::set<std::string>& hosts) {
@@ skipping 61 matching lines @@
 bool NTPSnippetsService::IsSyncStateIncompatible() {
   if (!sync_service_ || !sync_service_->CanSyncStart())
     return true;
   if (!sync_service_->IsSyncActive() || !sync_service_->ConfigurationDone())
     return false;  // Sync service is not initialized, yet not disabled.
   return !sync_service_->GetActiveDataTypes().Has(
       syncer::HISTORY_DELETE_DIRECTIVES);
 }
 
 }  // namespace ntp_snippets