function displaySongInPlaylistWaveform(element, svg, playlist, song) {
    /*
      Ensure it's the active song in the active playlist.
    */
    if (_config2.default.active_playlist == playlist && _config2.default.playlists[_config2.default.active_playlist].active_index == song) {
      var waveformPath = element.querySelector("svg g path");

      waveformPath.setAttribute("d", svg);
    }
  }
Displays a song in playlist waveform.

@param {Node} element - Element to display the waveform in.
@param {SVG} svg - The waveform path.
@param {String} playlist - The playlist the waveform is in.
@param {Integer} song - The index of the song we are displaying the waveform for.