InlinedVisitor: Migrate encryptedmedia to use inlined tracing

Source/modules/encryptedmedia/MediaKeys.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 45 matching lines @@
     // FIXME: This should be removed after crbug.com/425186 is fully
     // implemented.
     const String& keySystem() const { return m_keySystem; }
 
     MediaKeySession* createSession(ScriptState*, const String& sessionType, ExceptionState&);
 
     ScriptPromise setServerCertificate(ScriptState*, const DOMArrayPiece& serverCertificate);
 
     blink::WebContentDecryptionModule* contentDecryptionModule();
 
-    virtual void trace(Visitor*) override;
+    DECLARE_VIRTUAL_TRACE();
 
     // ContextLifecycleObserver
     virtual void contextDestroyed() override;
 
 private:
     class PendingAction;
 
     void timerFired(Timer<MediaKeys>*);
 
     const String m_keySystem;
     const blink::WebVector<blink::WebString> m_supportedSessionTypes;
     OwnPtr<blink::WebContentDecryptionModule> m_cdm;
 
     HeapDeque<Member<PendingAction>> m_pendingActions;
     Timer<MediaKeys> m_timer;
 };
 
 } // namespace blink
 
 #endif // MediaKeys_h