Convert Event#keyIdentifier (deprecated) to Event#key

ui/webui/resources/js/cr/ui/tabs.js

Index: ui/webui/resources/js/cr/ui/tabs.js
diff --git a/ui/webui/resources/js/cr/ui/tabs.js b/ui/webui/resources/js/cr/ui/tabs.js
index 512c729444a5f804db85b56be39ee089adf575df..d3256d8f345ac8035511232ad77f0a3e3652d1c4 100644
--- a/ui/webui/resources/js/cr/ui/tabs.js
+++ b/ui/webui/resources/js/cr/ui/tabs.js
@@ -150,13 +150,13 @@ cr.define('cr.ui', function() {
      */
     handleKeyDown_: function(e) {
       var delta = 0;
-      switch (e.keyIdentifier) {
-        case 'Left':
-        case 'Up':
+      switch (e.key) {
+        case 'ArrowLeft':
+        case 'ArrowUp':
           delta = -1;
           break;
-        case 'Right':
-        case 'Down':
+        case 'ArrowRight':
+        case 'ArrowDown':
           delta = 1;
           break;
       }