Convert //base to use std::unique_ptr

base/json/json_parser.h

Index: base/json/json_parser.h
diff --git a/base/json/json_parser.h b/base/json/json_parser.h
index fc04594a14924340c32123da632b4150210a0917..304edd1ac844911456c07277fdf396af0b93b5e8 100644
--- a/base/json/json_parser.h
+++ b/base/json/json_parser.h
@@ -133,7 +133,7 @@ class BASE_EXPORT JSONParser {
     size_t length_;
 
     // The copied string representation. NULL until Convert() is called.
-    // Strong. scoped_ptr<T> has too much of an overhead here.
+    // Strong. std::unique_ptr<T> has too much of an overhead here.
     std::string* string_;
   };