config.action_controller.asset_host shouldn't set to nil during precompile

actionpack/lib/sprockets/assets.rake

@@ -17,9 +17,6 @@ namespace :assets do
       # Always compile files
       Rails.application.config.assets.compile = true
 
-      # Always ignore asset host
-      Rails.application.config.action_controller.asset_host = nil
-
       config = Rails.application.config
       env    = Rails.application.assets
       target = Pathname.new(File.join(Rails.public_path, config.assets.prefix))

railties/test/application/assets_test.rb

@@ -270,20 +270,6 @@ module ApplicationTests
       assert_match(/\/assets\/rails-([0-z]+)\.png/, File.read(file))
     end
 
-    test "precompile ignore asset_host" do
-      app_file "app/assets/javascripts/application.css.erb", "<%= asset_path 'rails.png' %>"
-      add_to_config "config.action_controller.asset_host = Proc.new { |source, request| 'http://www.example.com/' }"
-
-      capture(:stdout) do
-        Dir.chdir(app_path){ `bundle exec rake assets:precompile` }
-      end
-
-      file = Dir["#{app_path}/public/assets/application.css"].first
-      content = File.read(file)
-      assert_match(/\/assets\/rails.png/, content)
-      assert_no_match(/www\.example\.com/, content)
-    end
-
     test "precompile should handle utf8 filenames" do
       app_file "app/assets/images/レイルズ.png", "not a image really"
       add_to_config "config.assets.precompile = [ /\.png$$/, /application.(css|js)$/ ]"