Add support for KeyboardEvent.location attribute

LayoutTests/fast/events/script-tests/keydown-numpad-keys.js

 description("This tests keyboard events with KeyLocationCode argument.");
 
 var lastKeyboardEvent;
 
 function recordKeyEvent(ev) {
     ev = ev || event;
     ev.keyCode = (ev.which || ev.keyCode);
     if (window.eventSender) {
         lastKeyboardEvent = ev;
     } else {
         debug('Type=' + ev.type + ',' +
               'keyCode=' + ev.keyCode + ',' +
               'ctrlKey=' + ev.ctrlKey + ',' +
               'shiftKey=' + ev.shiftKey + ',' +
               'altKey=' + ev.altKey + ',' +
               'metaKey=' + ev.metaKey + ',' +
-              'location=' + ev.keyLocation);
+              'location=' + ev.location);
     }
 }
 
 function testKeyEventWithLocation(evString, evLocation, expectedKeyCode) {
     eventSender.keyDown(evString, [], evLocation);
     shouldBe("lastKeyboardEvent.type", '"keydown"');
     shouldEvaluateTo("lastKeyboardEvent.keyCode", expectedKeyCode);
-    shouldEvaluateTo("lastKeyboardEvent.keyLocation", evLocation);
+    shouldEvaluateTo("lastKeyboardEvent.location", evLocation);
 }
 
 var textarea = document.createElement("textarea");
 textarea.addEventListener("keydown", recordKeyEvent, false);
 document.body.insertBefore(textarea, document.body.firstChild);
 textarea.focus();
 
 if (window.eventSender) {
     // location=0 indicates that we send events as standard keys.
     testKeyEventWithLocation("pageUp", 0, 33);
@@ skipping 14 matching lines @@
     testKeyEventWithLocation("end", 3, 35);
     testKeyEventWithLocation("leftArrow", 3, 37);
     testKeyEventWithLocation("rightArrow", 3, 39);
     testKeyEventWithLocation("upArrow", 3, 38);
     testKeyEventWithLocation("downArrow", 3, 40);
     testKeyEventWithLocation("insert", 3, 45);
     testKeyEventWithLocation("delete", 3, 46);
 } else {
     debug("This test requires DumpRenderTree.  To manually test, 1) focus on the textarea above and push numpad keys without locking NumLock and 2) see if the location= value is 3 (DOM_KEY_LOCATION_NUMPAD specified in DOM level 3).");
 }