_autocomplete.base.scss

// Animated throbber
html.js .form-autocomplete {
  background-image: image-url('svg/throbber-inactive.svg');
  background-position: 95% center;
  background-position: -webkit-calc(100% - 5px) center;
  background-position: calc(100% - 5px) center;
  background-repeat: no-repeat;
}

html.js .throbbing {
  background-image: image-url('svg/throbber.svg');
}

throbber-inactive.svg

throbber.svg

<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 300 300">
  <path d="M 150,0
    a 150,150 0 0,1 106,256
    l -35,-35
    a -100,-100 0 0,0 -70,-170 z"
    fill="#0e93d5">
    <animateTransform attributeName="transform" attributeType="XML"
      type="rotate" from="0 150 150" to="360 150 150"
      begin="0s" dur="1s" fill="freeze" repeatCount="indefinite" />
  </path>
</svg>