Sync event interfaces with the UI Events spec

Source/core/events/KeyboardEventInit.idl

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// http://www.w3.org/TR/DOM-Level-3-Events/#interface-KeyboardEvent
-// Note: this event init is somewhat different from the spec for compatibility reason.
+// https://w3c.github.io/uievents/#idl-def-KeyboardEventInit
 
-dictionary KeyboardEventInit : SharedKeyboardAndMouseEventInit {
+dictionary KeyboardEventInit : EventModifierInit {
+    // TODO(philipj): DOMString key = "";
+    // TODO(philipj): DOMString code = "";
+    unsigned long location = 0;
+    boolean repeat = false;
+    // TODO(philipj): boolean isComposing = false;
+
+    // Non-standard APIs
     DOMString keyIdentifier = "";
-    unsigned long location = 0;
-    [ImplementedAs=location, DeprecateAs=KeyboardEventKeyLocation] unsigned long keyLocation = 0; // Deprecated.
-    boolean repeat = false;
+    [ImplementedAs=location, DeprecateAs=KeyboardEventKeyLocation] unsigned long keyLocation = 0;
 };