# File lib/css_parser.rb, line 147
  def self.convert_uris(css, base_uri)
    base_uri = Addressable::URI.parse(base_uri) unless base_uri.kind_of?(Addressable::URI)

    css.gsub(URI_RX) do
      uri = $1.to_s
      uri.gsub!(/["']+/, '')
      # Don't process URLs that are already absolute
      unless uri =~ /^[a-z]+\:\/\//i
        begin
          uri = base_uri + uri
        rescue; end
      end
      "url('#{uri.to_s}')"
    end
  end