Use object instead of string.

Author: JunichiIto

lib/rails/html/sanitizer.rb

@@ -106,8 +106,8 @@ def sanitize(html, options = {})
         return unless html
         return html if html.empty?
 
-        encoding = html.encoding.name == 'ASCII-8BIT' ? 'UTF-8' : html.encoding.name
-        loofah_fragment = Loofah.fragment(html, encoding)
+        encoding = html.encoding == Encoding::ASCII_8BIT ? Encoding::UTF_8 : html.encoding
+        loofah_fragment = Loofah.fragment(html, encoding.name)
 
         if scrubber = options[:scrubber]
           # No duck typing, Loofah ensures subclass of Loofah::Scrubber