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

chrome/browser/ui/webui/options/certificate_manager_handler.cc

Index: chrome/browser/ui/webui/options/certificate_manager_handler.cc
diff --git a/chrome/browser/ui/webui/options/certificate_manager_handler.cc b/chrome/browser/ui/webui/options/certificate_manager_handler.cc
index bc53b77092f01499824b0e2f5f68fc046e989553..3b04414b20c1ebf60e04c15b2e0a88cb6399afd3 100644
--- a/chrome/browser/ui/webui/options/certificate_manager_handler.cc
+++ b/chrome/browser/ui/webui/options/certificate_manager_handler.cc
@@ -87,14 +87,14 @@ struct DictionaryIdComparator {
       : collator_(collator) {
   }
 
-  bool operator()(const base::Value* a,
-                  const base::Value* b) const {
-    DCHECK(a->GetType() == base::Value::TYPE_DICTIONARY);
-    DCHECK(b->GetType() == base::Value::TYPE_DICTIONARY);
-    const base::DictionaryValue* a_dict =
-        reinterpret_cast<const base::DictionaryValue*>(a);
-    const base::DictionaryValue* b_dict =
-        reinterpret_cast<const base::DictionaryValue*>(b);
+  bool operator()(const std::unique_ptr<base::Value>& a,
+                  const std::unique_ptr<base::Value>& b) const {
+    const base::DictionaryValue* a_dict;
+    if (!a->GetAsDictionary(&a_dict))
+      NOTREACHED();

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

nit: I a lil bit prefer

bool a_is_dictionary = a->GetAsDictionary(&a_dict);
DCHECK(a_is_dictionary);

cuz NOTREACHED has the most useless output of them all.

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

Done. I don't feel super strongly, but I actually prefer the existing way for
two reasons:
- Having to explicitly name the DCHECKed thing is kind of annoying (since it
duplicates the information about what operation is being done)
- Having no indent makes the code harder to read here (IMO). NOTREACHED() may
not have useful output, but since this should never "happen", I prefer to
optimize for the code reader to make that easier to see.

What I'd really like is a DCHECK variant that always executes the statement, but
that would be confusing.

+    const base::DictionaryValue* b_dict;
+    if (!b->GetAsDictionary(&b_dict))
+      NOTREACHED();
     base::string16 a_str;
     base::string16 b_str;
     a_dict->GetString(kNameId, &a_str);