module Sprockets::Processing

def css_compressor=(compressor)

The compressor object must respond to `compress` or `compile`.

Assign a compressor to run on `text/css` assets.

def css_compressor=(compressor)
  expire_index!
  unregister_bundle_processor 'text/css', :css_compressor
  return unless compressor
  register_bundle_processor 'text/css', :css_compressor do |context, data|
    compressor.compress(data)
  end
end