Add MediaKeySession.keystatuseschange event

Source/modules/encryptedmedia/MediaKeySession.h

 /*
  * 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 84 matching lines @@
 
     MediaKeySession(ScriptState*, MediaKeys*, const String& sessionType);
 
     void actionTimerFired(Timer<MediaKeySession>*);
 
     // WebContentDecryptionModuleSession::Client
     virtual void message(MessageType, const unsigned char* message, size_t messageLength) override;
     virtual void message(const unsigned char* message, size_t messageLength, const WebURL& destinationURL) override;
     virtual void close() override;
     virtual void expirationChanged(double updatedExpiryTimeInMS) override;
+    virtual void keysStatusesChange(const WebVector<WebEncryptedMediaKeyInformation>&, bool hasAdditionalUsableKey) override;
 
     // Called by NewSessionResult when the new session has been created.
     void finishGenerateRequest();
 
     // Called by LoadSessionResult when the session has been loaded.
     void finishLoad();
 
     String m_keySystem;
     OwnPtrWillBeMember<GenericEventQueue> m_asyncEventQueue;
     OwnPtr<WebContentDecryptionModuleSession> m_session;
@@ skipping 14 matching lines @@
     typedef ScriptPromiseProperty<Member<MediaKeySession>, ToV8UndefinedGenerator, RefPtrWillBeMember<DOMException> > ClosedPromise;
     Member<ClosedPromise> m_closedPromise;
 
     HeapDeque<Member<PendingAction> > m_pendingActions;
     Timer<MediaKeySession> m_actionTimer;
 };
 
 } // namespace blink
 
 #endif // MediaKeySession_h