Untrusted textInput event

How to restore Chrome 52 default action behavior?

HTML

Watch console logs and try typing Ctrl+Shift+/ in this input box to get an "‽".<br />
<input type="text" SIZE="40" MAXLENGTH="80" id="textbox"><br>
<textarea>aaaa</textarea>

JavaScript

window.addEventListener("keydown", function(event) {
  var modifier = event.ctrlKey || event.metaKey;
  if (modifier && event.shiftKey && event.keyCode == 191) {
  	document.execCommand( 'insertText', false, String.fromCharCode(8253));
    }
}, false);

window.addEventListener("input", function(e) {
		console.log("Received a" + (e.isTrusted ? " " : "n un") + "trusted event", e);
});