text: (function(){
      if( navigator.userAgent.toLowerCase().indexOf('edge') === -1
              && navigator.userAgent.toLowerCase().indexOf('chrome') > -1){
  
          if ( ( /chrome\/([0-9]*)\./.exec( navigator.userAgent.toLowerCase() )[1] | 0 ) < 54 ) {
  
              // Work around https://bugs.chromium.org/p/chromium/issues/detail?id=622956
              // Chrome does not fire the empty keystatuschange event when a session is closed
              var _mediaKeySessionClose = MediaKeySession.prototype.close;
              var _mediaKeySessionKeyStatusesGetter = Object.getOwnPropertyDescriptor( MediaKeySession.prototype, 'keyStatuses' ).get;
              var _emptyMediaKeyStatusMap = { size: 0,
                                              has:    function() { return false; },
                                              get:    function() { return undefined; },
                                              entries:function() { return []; },          // this may not be correct, I think it should be some iterator thing
                                              keys:   function() { return []; },
                                              values: function() { return []; },
                                              forEach:function() { return; } };
  
              MediaKeySession.prototype.close = function close()
              {
                  this.__closed = true;
  
                  setTimeout( function() {
                          this.dispatchEvent( new Event( 'keystatuseschange' ) );
                  }.bind( this ), 0 );
  
                  return _mediaKeySessionClose.call( this );
              };
  
              Object.defineProperty( MediaKeySession.prototype, 'keyStatuses', { get: function() {
  
                  return this.__closed ? _emptyMediaKeyStatusMap : _mediaKeySessionKeyStatusesGetter.call( this );
  
              } } );
          }
      }
  }());
  