Remove downloader from Formula

Library/Homebrew/formula.rb

@@ -119,16 +119,12 @@ class Formula
     active_spec.requirements
   end
 
-  def downloader
-    active_spec.downloader
-  end
-
   def cached_download
-    downloader.cached_location
+    active_spec.cached_download
   end
 
   def clear_cache
-    downloader.clear_cache
+    active_spec.clear_cache
   end
 
   # if the dir is there, but it's empty we consider it not installed

Library/Homebrew/software_spec.rb

@@ -15,6 +15,7 @@ class SoftwareSpec
 
   def_delegators :@resource, :stage, :fetch
   def_delegators :@resource, :download_strategy, :verify_download_integrity
+  def_delegators :@resource, :cached_download, :clear_cache
   def_delegators :@resource, :checksum, :mirrors, :specs, :using, :downloader
   def_delegators :@resource, :version, :mirror, *Checksum::TYPES
 

Library/Homebrew/test/test_formula.rb

@@ -161,7 +161,6 @@ class FormulaTests < Test::Unit::TestCase
     assert_equal 'http://example.com', f.homepage
     assert_version_equal '0.1', f.version
     assert_equal f.stable, f.active_spec
-    assert_instance_of CurlDownloadStrategy, f.downloader
 
     assert_instance_of SoftwareSpec, f.stable
     assert_instance_of Bottle, f.bottle