Revert r189385 "Remove LifecycleContext" and r189391, r189530, r189456 that block it

Source/core/dom/ActiveDOMObject.h

 /*
  * Copyright (C) 2008 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 16 matching lines @@
 #ifndef ActiveDOMObject_h
 #define ActiveDOMObject_h
 
 #include "core/dom/ContextLifecycleObserver.h"
 #include "wtf/Assertions.h"
 
 namespace blink {
 
 class ActiveDOMObject : public ContextLifecycleObserver {
 public:
-    explicit ActiveDOMObject(ExecutionContext*);
+    ActiveDOMObject(ExecutionContext*);
 
     // suspendIfNeeded() should be called exactly once after object construction to synchronize
     // the suspend state with that in ExecutionContext.
     void suspendIfNeeded();
 #if ENABLE(ASSERT)
     bool suspendIfNeededCalled() const { return m_suspendIfNeededCalled; }
 #endif
 
     // Should return true if there's any pending asynchronous activity, and so
     // this object must not be garbage collected.
@@ skipping 12 matching lines @@
 
 private:
 #if ENABLE(ASSERT)
     bool m_suspendIfNeededCalled;
 #endif
 };
 
 } // namespace blink
 
 #endif // ActiveDOMObject_h