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

chrome/browser/extensions/api/content_settings/content_settings_store.cc

 // Copyright (c) 2012 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/extensions/api/content_settings/content_settings_store.h"
 
 #include <memory>
 #include <set>
 #include <utility>
 #include <vector>
@@ skipping 270 matching lines @@
       settings->Append(setting_dict);
     }
   }
   return settings;
 }
 
 void ContentSettingsStore::SetExtensionContentSettingFromList(
     const std::string& extension_id,
     const base::ListValue* list,
     ExtensionPrefsScope scope) {
-  for (base::ListValue::const_iterator it = list->begin();
-       it != list->end(); ++it) {
-    if ((*it)->GetType() != base::Value::TYPE_DICTIONARY) {
+  for (const auto& value : *list) {
+    base::DictionaryValue* dict;
+    if (value->GetAsDictionary(&dict)) {

[danakj, 2016/05/24 20:08:34]

do you mean if (!GetAsDictionary) ?

[dcheng, 2016/05/24 20:39:02]

Yes. =X

       NOTREACHED();
       continue;

[danakj, 2016/05/24 20:08:34]

ಠ_ಠ Should either DCHECK or continue not both. I see this is a popular meme with
value iteration.

[dcheng, 2016/05/24 20:39:02]

Yeah, I think I'd rather not change the semantics of existing code if I can
avoid it though.

     }
-    base::DictionaryValue* dict = static_cast<base::DictionaryValue*>(*it);
     std::string primary_pattern_str;
     dict->GetString(keys::kPrimaryPatternKey, &primary_pattern_str);
     ContentSettingsPattern primary_pattern =
         ContentSettingsPattern::FromString(primary_pattern_str);
     DCHECK(primary_pattern.IsValid());
 
     std::string secondary_pattern_str;
     dict->GetString(keys::kSecondaryPatternKey, &secondary_pattern_str);
     ContentSettingsPattern secondary_pattern =
         ContentSettingsPattern::FromString(secondary_pattern_str);
@@ skipping 64 matching lines @@
 ContentSettingsStore::FindEntry(const std::string& ext_id) const {
   ExtensionEntryMap::const_iterator i;
   for (i = entries_.begin(); i != entries_.end(); ++i) {
     if (i->second->id == ext_id)
       return i;
   }
   return entries_.end();
 }
 
 }  // namespace extensions