Implement navigator.requestMediaKeySystemAccess()

Source/modules/encryptedmedia/MediaKeys.idl

 /*
  * Copyright (C) 2013 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 15 matching lines @@
 enum SessionType {
     "temporary",
     "persistent"
 };
 
 [
     RuntimeEnabled=EncryptedMedia,
     GarbageCollected,
     TypeChecking=Interface
 ] interface MediaKeys {
-    readonly attribute DOMString keySystem;
-
     [CallWith=ScriptState] MediaKeySession createSession(optional SessionType sessionType = "temporary");
 
     [CallWith=ScriptState] Promise setServerCertificate(ArrayBuffer serverCertificate);
     [CallWith=ScriptState] Promise setServerCertificate(ArrayBufferView serverCertificate);
 
-    [CallWith=ScriptState] static Promise create(DOMString keySystem);
-
     static boolean isTypeSupported(DOMString keySystem, optional DOMString contentType = null);
 };