Handle the "key" field as opposed to keyIdentifier field.

third_party/WebKit/LayoutTests/fast/events/simulated-key-state.html

 <p>This tests that modifier keys are propagated to the fake mouse event created when you press return and a link has focus.</p>
 <p>If the test succeeds, you should see six "PASS" messages below.</p>
 <p>This is the <a id="link" href="#" onclick="checkKeyState(event)" onmousedown="checkKeyState(event)" onmouseuup="checkKeyState(event)">link</a> used for testing.</p>
 <pre id="console">
 </pre>
 <script>
 
 if (window.testRunner)
     testRunner.dumpAsText();
 
 var link = document.getElementById("link");
 link.focus();
 
 var expectedCtrl;
 var expectedAlt;
 var expectedShift;
 var expectedMeta;
 
 function test(ctrlKey, altKey, shiftKey, metaKey)
 {
     expectedCtrl = ctrlKey;
     expectedAlt = altKey;
     expectedShift = shiftKey;
     expectedMeta = metaKey;
-    var event = document.createEvent("KeyboardEvents");
-    event.initKeyboardEvent("keydown", true, true, document.defaultView, "Enter", 0, ctrlKey, altKey, shiftKey, metaKey, false);
+    var event = new KeyboardEvent("keydown", {bubbles: true, cancelable: true, view: document.defaultView, key: "Enter", ctrlKey: ctrlKey, altKey: altKey, shiftKey: shiftKey, metaKey: metaKey});
     link.dispatchEvent(event);
 }
 
 function checkKeyState(event)
 {
     if (event.ctrlKey == expectedCtrl && event.altKey == expectedAlt && event.shiftKey == expectedShift && event.metaKey == expectedMeta)
         document.getElementById("console").innerHTML += "PASS: " + event.type + " event had all the right key state.\n";
     else
         document.getElementById("console").innerHTML += "FAIL: " + event.type + " event did not have the right key state.\n";
 }
 
 test(false, false, false, false);
 test(true, false, false, false);
 test(false, true, false, false);
 test(false, false, true, false);
 test(false, false, false, true);
 test(true, true, true, true);
 
 link.blur();
 
 </script>