name-component: recognize plain URI syntax

refs #4690

Change-Id: I6e88d88cc62a025edc30b545f1044a225c20213f
diff --git a/src/name-component.hpp b/src/name-component.hpp
index 9f8de4f..9340176 100644
--- a/src/name-component.hpp
+++ b/src/name-component.hpp
@@ -212,7 +212,7 @@
    * @throw Error URI component does not represent a valid NameComponent.
    */
   static Component
-  fromEscapedString(std::string input);
+  fromEscapedString(const std::string& input);
 
   /**
    * @brief Write *this to the output stream, escaping characters according to the NDN URI Scheme