Simplify Supplementables post Oilpan.

third_party/WebKit/Source/core/dom/ExecutionContext.h

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * 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
@@ skipping 40 matching lines @@
 class ErrorEvent;
 class EventQueue;
 class EventTarget;
 class ExecutionContextTask;
 class LocalDOMWindow;
 class OriginTrialContext;
 class PublicURLManager;
 class SecurityOrigin;
 class ScriptCallStack;
 
-class CORE_EXPORT ExecutionContext
-    : public ContextLifecycleNotifier, public HeapSupplementable<ExecutionContext> {
+class CORE_EXPORT ExecutionContext : public ContextLifecycleNotifier, public Supplementable<ExecutionContext> {
     WTF_MAKE_NONCOPYABLE(ExecutionContext);
 public:
     DECLARE_VIRTUAL_TRACE();
 
     // Used to specify whether |isSecureContext| should walk the
     // ancestor tree to decide whether to restrict usage of a powerful
     // feature.
     enum SecureContextCheck {
         StandardSecureContextCheck,
         WebCryptoSecureContextCheck
@@ skipping 123 matching lines @@
 
     Deque<OwnPtr<SuspendableTask>> m_suspendedTasks;
     bool m_isRunSuspendableTasksScheduled;
 
     ReferrerPolicy m_referrerPolicy;
 };
 
 } // namespace blink
 
 #endif // ExecutionContext_h