Revert of Explicit notification and removal of lifecycle observers.

Source/core/dom/ContextLifecycleNotifier.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2013 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 46 matching lines @@
 {
     LifecycleNotifier<ExecutionContext>::removeObserver(observer);
 
     RELEASE_ASSERT(m_iterating != IteratingOverContextObservers);
     if (observer->observerType() == Observer::ActiveDOMObjectType) {
         RELEASE_ASSERT(m_iterating != IteratingOverActiveDOMObjects);
         m_activeDOMObjects.remove(static_cast<ActiveDOMObject*>(observer));
     }
 }
 
-void ContextLifecycleNotifier::removeAndNotifyAllObservers()
-{
-    LifecycleNotifier<ExecutionContext>::removeAndNotifyAllObservers();
-    m_activeDOMObjects.clear();
-}
-
 void ContextLifecycleNotifier::notifyResumingActiveDOMObjects()
 {
     TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverActiveDOMObjects);
     ActiveDOMObjectSet::iterator activeObjectsEnd = m_activeDOMObjects.end();
     for (ActiveDOMObjectSet::iterator iter = m_activeDOMObjects.begin(); iter != activeObjectsEnd; ++iter) {
         ASSERT((*iter)->executionContext() == context());
         ASSERT((*iter)->suspendIfNeededCalled());
         (*iter)->resume();
     }
 }
@@ skipping 36 matching lines @@
     ActiveDOMObjectSet::const_iterator activeObjectsEnd = activeDOMObjects().end();
     for (ActiveDOMObjectSet::const_iterator iter = activeDOMObjects().begin(); iter != activeObjectsEnd; ++iter) {
         if ((*iter)->hasPendingActivity())
             return true;
     }
 
     return false;
 }
 
 } // namespace WebCore