Revert of Prefer using ContextClient over ContextLifecycleObserver

third_party/WebKit/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 75 matching lines @@
 
   // The previously reserved and accepted HTMLMediaElement is no longer
   // using this object.
   void clearMediaElement();
 
   WebContentDecryptionModule* contentDecryptionModule();
 
   DECLARE_VIRTUAL_TRACE();
 
   // ContextLifecycleObserver implementation.
+  // FIXME: This class could derive from ContextLifecycleObserver
+  // again (http://crbug.com/483722).
   void contextDestroyed() override;
 
   // ScriptWrappable implementation.
   bool hasPendingActivity() const final;
 
  private:
   MediaKeys(
       ExecutionContext*,
       const WebVector<WebEncryptedMediaSessionType>& supportedSessionTypes,
       std::unique_ptr<WebContentDecryptionModule>);
@@ skipping 19 matching lines @@
   // object will be prevented until the setMediaKeys() completes.
   bool m_reservedForMediaElement;
 
   HeapDeque<Member<PendingAction>> m_pendingActions;
   Timer<MediaKeys> m_timer;
 };
 
 }  // namespace blink
 
 #endif  // MediaKeys_h