url('/data/perspective/icons/material.svg#insert_emoticon')
hehe you'll need to add some sizes to it
might be easier to use it as background img than instead (need a, nonemtpy content still tho)
styles=".iaDropdownCommon_options [data-label='YourLabel']:before { padding:10px; content:' '; background-image: url('/data/perspective/icons/material.svg#insert_emoticon'); }"