Optimize DetailsKey generation.

actionpack/lib/action_view/lookup_context.rb

@@ -38,17 +38,18 @@ module Setters #:nodoc:
     register_detail(:locale)  { [I18n.locale] }
 
     class DetailsKey #:nodoc:
-      attr_reader :details
       alias :eql? :equal?
+      alias :object_hash :hash
 
+      attr_reader :hash
       @details_keys = Hash.new
 
       def self.get(details)
-        @details_keys[details] ||= new(details)
+        @details_keys[details] ||= new
       end
 
-      def initialize(details)
-        @details, @hash = details, details.hash
+      def initialize
+        @hash = object_hash
       end
     end