Use Resource#downloader for BottleLoader.

Library/Homebrew/formulary.rb

@@ -105,7 +105,7 @@ module Formulary
         formula_name = File.basename(bottle_name)[/(.+)-/, 1]
         resource = Resource.new(formula_name) { url bottle_name }
         resource.specs[:bottle] = true
-        downloader = CurlDownloadStrategy.new(resource.download_name, resource.version, resource)
+        downloader = resource.downloader
         cached = downloader.cached_location.exist?
         downloader.fetch
         ohai "Pouring the cached bottle" if cached

Library/Homebrew/resource.rb

@@ -64,7 +64,9 @@ class Resource
   end
 
   def download_name
-    name.nil? ? owner.name : "#{owner.name}--#{escaped_name}"
+    return owner.name if name.nil?
+    return escaped_name if owner.nil?
+    "#{owner.name}--#{escaped_name}"
   end
 
   def cached_download