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

components/ntp_snippets/ntp_snippet.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_snippet.h"
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/values.h"
 
@@ skipping 53 matching lines @@
   std::string expiry_timestamp_str;
   if (content->GetString(kExpiryDate, &expiry_timestamp_str))
     snippet->set_expiry_date(TimeFromJsonString(expiry_timestamp_str));
 
   const base::ListValue* corpus_infos_list = nullptr;
   if (!content->GetList(kSourceCorpusInfo, &corpus_infos_list)) {
     DLOG(WARNING) << "No sources found for article " << title;
     return nullptr;
   }
 
-  for (base::Value* value : *corpus_infos_list) {
+  for (const auto& value : *corpus_infos_list) {
     const base::DictionaryValue* dict_value = nullptr;
     if (!value->GetAsDictionary(&dict_value)) {
       DLOG(WARNING) << "Invalid source info for article " << id;
       continue;
     }
 
     std::string corpus_id_str;
     GURL corpus_id;
     if (dict_value->GetString(kCorpusId, &corpus_id_str))
       corpus_id = GURL(corpus_id_str);
@@ skipping 57 matching lines @@
   double score;
   if (dict.GetDouble(kScore, &score))
     snippet->set_score(score);
 
   return snippet;
 }
 
 // static
 bool NTPSnippet::AddFromListValue(const base::ListValue& list,
                                   PtrVector* snippets) {
-  for (const base::Value* const value : list) {
+  for (const auto& value : list) {
     const base::DictionaryValue* dict = nullptr;
     if (!value->GetAsDictionary(&dict))
       return false;
 
     std::unique_ptr<NTPSnippet> snippet = CreateFromDictionary(*dict);
     if (!snippet)
       return false;
 
     snippets->push_back(std::move(snippet));
   }
@@ skipping 51 matching lines @@
   }
   return base::Time::UnixEpoch() + base::TimeDelta::FromSeconds(timestamp);
 }
 
 // static
 std::string NTPSnippet::TimeToJsonString(const base::Time& time) {
   return base::Int64ToString((time - base::Time::UnixEpoch()).InSeconds());
 }
 
 }  // namespace ntp_snippets