[NTP Snippets] Refactor home-grown container API

chrome/browser/ui/webui/snippets_internals_message_handler.cc

 // Copyright 2016 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 "chrome/browser/ui/webui/snippets_internals_message_handler.h"
 
 #include <memory>
 #include <set>
 #include <vector>
 
@@ skipping 159 matching lines @@
   SendString("hosts-help", help);
 
   SendSnippets();
   SendDiscardedSnippets();
 }
 
 void SnippetsInternalsMessageHandler::SendSnippets() {
   std::unique_ptr<base::ListValue> snippets_list(new base::ListValue);
 
   int index = 0;
-  for (auto& snippet : *ntp_snippets_service_)
-    snippets_list->Append(PrepareSnippet(snippet, index++, false));
+  for (const std::unique_ptr<ntp_snippets::NTPSnippet>& snippet :
+       ntp_snippets_service_->snippets())
+    snippets_list->Append(PrepareSnippet(*snippet, index++, false));
 
   base::DictionaryValue result;
   result.Set("list", std::move(snippets_list));
   web_ui()->CallJavascriptFunction("chrome.SnippetsInternals.receiveSnippets",
                                    result);
 
   const std::string& status = ntp_snippets_service_->last_status();
   if (!status.empty())
     SendString("hosts-status", "Finished: " + status);
 }
 
 void SnippetsInternalsMessageHandler::SendDiscardedSnippets() {
   std::unique_ptr<base::ListValue> snippets_list(new base::ListValue);
 
   int index = 0;
-  for (auto& snippet : ntp_snippets_service_->discarded_snippets())
+  for (const auto& snippet : ntp_snippets_service_->discarded_snippets())
     snippets_list->Append(PrepareSnippet(*snippet, index++, true));
 
   base::DictionaryValue result;
   result.Set("list", std::move(snippets_list));
   web_ui()->CallJavascriptFunction(
       "chrome.SnippetsInternals.receiveDiscardedSnippets", result);
 }
 
 void SnippetsInternalsMessageHandler::SendHosts() {
   std::unique_ptr<base::ListValue> hosts_list(new base::ListValue);
@@ skipping 25 matching lines @@
 }
 
 void SnippetsInternalsMessageHandler::SendString(const std::string& name,
                                                  const std::string& value) {
   base::StringValue string_name(name);
   base::StringValue string_value(value);
 
   web_ui()->CallJavascriptFunction("chrome.SnippetsInternals.receiveProperty",
                                    string_name, string_value);
 }