Add new needkey event for EME.

Source/modules/encryptedmedia/MediaKeyNeededEvent.cpp

 /*
  * Copyright (C) 2012 Google 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 24 matching lines @@
 {
 }
 
 MediaKeyNeededEvent::MediaKeyNeededEvent()
 {
     ScriptWrappable::init(this);
 }
 
 MediaKeyNeededEvent::MediaKeyNeededEvent(const AtomicString& type, const MediaKeyNeededEventInit& initializer)
     : Event(type, initializer)
+    , m_contentType(initializer.contentType)
     , m_initData(initializer.initData)
 {
     ScriptWrappable::init(this);
 }
 
 MediaKeyNeededEvent::~MediaKeyNeededEvent()
 {
 }
 
 const AtomicString& MediaKeyNeededEvent::interfaceName() const
 {
     return EventNames::MediaKeyNeededEvent;
 }
 
 } // namespace WebCore