old_contents: // Copyright 2018, University of Colorado Boulder
  
  /**
   * Standard PhET button for 'info', uses the international symbol for 'information'.
   *
   * @author Chris Malley (PixelZoom, Inc.)
   */
  define( function( require ) {
    'use strict';
  
    // modules
    var FontAwesomeNode = require( 'SUN/FontAwesomeNode' );
    var inherit = require( 'PHET_CORE/inherit' );
    var RoundPushButton = require( 'SUN/buttons/RoundPushButton' );
    var sceneryPhet = require( 'SCENERY_PHET/sceneryPhet' );
  
    /**
     * @param {Object} [options]
     * @constructor
     */
    function InfoButton( options ) {
  
      options = _.extend( {
        minXMargin: 10,
        minYMargin: 10,
        touchAreaXDilation: 10,
        touchAreaYDilation: 5,
        baseColor: 'rgb( 238, 238, 238 )',
        iconFill: 'black'
      }, options );
  
      assert && assert( !options.content, 'InfoButton sets content' );
      options.content = new FontAwesomeNode( 'info_circle', {
        fill: options.iconFill
        // maxWidth: zoomInButton.width - chromeBounds.width - 2 * iconPadding,
        // maxHeight: zoomInButton.height - chromeBounds.height - 2 * iconPadding
      } );
  
      RoundPushButton.call( this, options );
    }
  
    sceneryPhet.register( 'InfoButton', InfoButton );
  
    return inherit( RoundPushButton, InfoButton );
  } );
new_contents: // Copyright 2018, University of Colorado Boulder
  
  /**
   * Standard PhET button for 'info', uses the international symbol for 'information'.
   *
   * @author Chris Malley (PixelZoom, Inc.)
   */
  define( function( require ) {
    'use strict';
  
    // modules
    var FontAwesomeNode = require( 'SUN/FontAwesomeNode' );
    var inherit = require( 'PHET_CORE/inherit' );
    var RoundPushButton = require( 'SUN/buttons/RoundPushButton' );
    var sceneryPhet = require( 'SCENERY_PHET/sceneryPhet' );
  
    /**
     * @param {Object} [options]
     * @constructor
     */
    function InfoButton( options ) {
  
      options = _.extend( {
        minXMargin: 10,
        minYMargin: 10,
        touchAreaXDilation: 10,
        touchAreaYDilation: 5,
        baseColor: 'rgb( 238, 238, 238 )',
        iconFill: 'black'
      }, options );
  
      assert && assert( !options.content, 'InfoButton sets content' );
      options.content = new FontAwesomeNode( 'info_circle', {
        fill: options.iconFill
      } );
  
      RoundPushButton.call( this, options );
    }
  
    sceneryPhet.register( 'InfoButton', InfoButton );
  
    return inherit( RoundPushButton, InfoButton );
  } );
subject: delete dead code #363