Add outside_app_allowed arg to find_templates

A backport of rails#23247 to 4-1-stable.

Author: maclover7

actionview/lib/action_view/template/resolver.rb

@@ -129,8 +129,8 @@ def find_all_anywhere(name, prefix, partial=false, details={}, key=nil, locals=[
     # This is what child classes implement. No defaults are needed
     # because Resolver guarantees that the arguments are present and
     # normalized.
-    def find_templates(name, prefix, partial, details)
-      raise NotImplementedError, "Subclasses must implement a find_templates(name, prefix, partial, details) method"
+    def find_templates(name, prefix, partial, details, outside_app_allowed = false)
+      raise NotImplementedError, "Subclasses must implement a find_templates(name, prefix, partial, details, outside_app_allowed) method"
     end
 
     # Helpers that builds a path. Useful for building virtual paths.