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

chrome/browser/plugins/plugin_prefs.cc

Index: chrome/browser/plugins/plugin_prefs.cc
diff --git a/chrome/browser/plugins/plugin_prefs.cc b/chrome/browser/plugins/plugin_prefs.cc
index 8d45ae4bc09d7f20f8c4f798ae5f20969a8231b3..6995dc913a155362c4ba740a06728a27c3babdb7 100644
--- a/chrome/browser/plugins/plugin_prefs.cc
+++ b/chrome/browser/plugins/plugin_prefs.cc
@@ -333,14 +333,13 @@ void PluginPrefs::SetPrefs(PrefService* prefs) {
     ListPrefUpdate update(prefs_, prefs::kPluginsPluginsList);
     base::ListValue* saved_plugins_list = update.Get();
     if (saved_plugins_list && !saved_plugins_list->empty()) {
-      for (base::Value* plugin_value : *saved_plugins_list) {
-        if (!plugin_value->IsType(base::Value::TYPE_DICTIONARY)) {
+      for (const auto& plugin_value : *saved_plugins_list) {
+        base::DictionaryValue* plugin;
+        if (!plugin_value->GetAsDictionary(&plugin)) {
           LOG(WARNING) << "Invalid entry in " << prefs::kPluginsPluginsList;
           continue;  // Oops, don't know what to do with this item.
         }
 
-        base::DictionaryValue* plugin =
-            static_cast<base::DictionaryValue*>(plugin_value);
         base::string16 group_name;
         bool enabled;
         if (!plugin->GetBoolean("enabled", &enabled))