Chrome [Violation] 'Load' Handler Took 808Ms

I worked with openlayer3. Now I got this kind of warning: Console:

[Violation] 'load' handler took 308ms  ol-debug.js.xhtml?ln=js:6967 
[Violation] 'load' handler took 808ms
ol.events.bindListener_ = function(listenerObj) {
  var boundListener = function(evt) { // <- Zeile 6967
    var listener = listenerObj.listener;
    var bindTo = listenerObj.bindTo || listenerObj.target;
    if (listenerObj.callOnce) {
      ol.events.unlistenByKey(listenerObj);
    }
    return listener.call(bindTo, evt);
  };
  listenerObj.boundListener = boundListener;
  return boundListener;
};

Is it maybe a bug on Google Chrome?

Thanks